Dreaded trans. Failsafe prog.
 

Doing about 60 yesterday and the abs/DSC light came one, pulled off to the side and trans.failsafe light came on and all I could do was limp mode. On my way to an important meeting. Switched off and back on and was able to drive the last Mike or two but no torque and didn’t shift properly. Got it back home and getting odd codes. All 4 oxy sensors, MAF low voltage , ICV mechanical failure.

Also 5A brief Power interrupter76, DME/DDE does not fulfill Torque request 3A no message from EGs control unit.

Suggested that I replace the battery but it’s 12.7 at rest and 14.17 running. Suggest to me that battery (less than a yr old) and the alt are good.

I also disconnected the ABS cable but no apparent effect.

I’ll check the fluid on Monday but I also smelled a burned smell but in heavy traffic, who knows.

Any diagnostic tips would help.

Thanks.


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What you described is exactly the classic example of alternator failure.

Clear all codes and watch vBat real-time. Best if done with a graph to catch short dips or spikes.

Usually the first sign is abs trifecta followed by possibly misfire/engine failsafe then transmission failsafe.

If any or most of that happens then you can clear the codes and it acts normal or else, will reset on their own it's almost always the alternator.

When near end of life the alternator can go through a bad day a few times and back to normal but if you monitor voltage on a groggy m graph you can usually pick up on the voltage dips.

How many miles (hours).

Divide odometer by average mph (for me about 160000/25=6400 hours). I was able to restore my alternator for $20 with a kit of brushes and slip rings. When wife's failed at a very similar hour life, I just changed the brushes and the polarity of the brushes so the other side of the slip rings would wear as only one gets 3x the wear of the other.

Consider: odds of all those different systems having a problem or the one thing they all run on (electricity) being the source of all the problems.

Kinda what I thought. Has to be electrical and I have had issues similar with an e46 that were fixed with a new battery.

Thanks. Reassuring.

Is an alternator rebuildable by a mediocre skilled shade tree guy?


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Dreaded trans. Failsafe prog.
 

Changing just the brushes is 2/10 difficulty. Slip rings 4/10 difficulty. It's easier than changing the alternator which is 5/10 or 7/10 (until you learn the nut insert trick)

It's very rare that a bad battery will cause problems while driving, it's usually that a new battery will mask voltage regulator problems buy acting as a voltage smoothing filter. Similar for a bad starter. As a starter starts to fail it takes more and more current to do its job, this will pull the voltage down do to resistance loses. A new battery will hide the problem and results in quick battery failure. Slow rpm long crank is a symptom of a bad starter not bad battery.

A freshly charged end of life battery will usually crank almost normal speed. (but may fail to crank 3 times in a row as the capacity is what goes away).

Dreaded trans. Failsafe prog.
 

Ok, terminology clarification.
Brushes=voltage regulator?

Nut insert trick?

Also, put my cheap scanner on it and both oxy sensors show 0 voltage.


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Dreaded trans. Failsafe prog.
 

Brushes are part of the VR. They run on the slip rings and how the armature gets power for the field windings. They are the primary wear part on an alternator.

The insert nut is a press fit steel nut that the main bolt for the alternator screws into. It's so tight a fit that it's extremely difficult to install when it's in its final position. Tapping it out to make even 1mm extra room decreases the difficulty level about 80%

It's possible to view the wrong type of O2 sensor and it will read zero.

Thanks.

The O2s have functioned well for the 10k Miles I have put on the car since I have had it. Just wondering if that further indicates Alternator prob or something else. MAF is getting 1volt.


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Can you read real-time vBat and better if you can graph it.

If you don't have a steady 13.6 or so, all bets are off

Once you've sorted out your voltage regulator test your MAF.
I have MAF issues all the time here (105f-125f) so getting a 1v reading on the MAF brings back the memories [emoji849]


The trick to checking your MAF is to tap the join (not loom connection) where the wire loom connects several times while idling with a screw driver handle (hard not breakable hard!) and if the engine stumbles it's time for a new one.

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Dreaded trans. Failsafe prog.
 

[mention]andrewwynn [/mention] where was this beautiful reply 2 months ago when I paid close to $1K to replace my alternator, pulleys and belt :-). I could have saved most of that money with your reverse the brushes trick. VERY CLEVER, I will have to remember that one!

https://xoutpost.com/bmw-sav-forums/...refurbish.html

Very detailed thread how to refurbish valeo Alternator.

Ok, so I finally pulled the alternator and had it tested by a certified recycler. 100% good.

Oddly, as I was pulling the alternation I noticed the connector was good and tight but the push in locking clip was missing. I have a replacement clip not a perfect fit but if I bend it a bit should work. Don’t think it’s the problem but the rebuilder said the alternator had been worked on at some point so I assume whoever reinstalled lost the clip and didn’t say anything about it…..

I’ll put it back together and see if I can get the clip to work, then move on if it’s not the problem..

Thanks.


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I'm not sure what the locking clip is there, but if you found something wrong, that is a good thing to fix, of course. Every connection to the alternator of course needs to be tight, clean, torqued properly on the plastic coated nut. Connections to the starter and jump port too. On these 3.0i's, the alt cable goes from the B+ connection on the alternator to the starter, then from the starter to the engine bay jump port, then through the jump port nut to the back side, then from there to the battery positive terminal, after making it through the pyro fuse.

But I would not put much (any?) faith in the "certified recycler" saying it is 100% good. From the beginning, your description of the problem shows it is intermittent. Sometimes present, sometimes not. If the tester checked it out when the problem was not present, they could give you a clear diagnosis that is wrong.

I agree with AndrewWynn's previous advice on this, other than that I would rate the difficulty of slip ring replacement as much harder. Andrew and I seem to be maybe the only ones on here that have done that procedure so far. I'd rate it an 8 out of 10, where 10 is brain surgery or a blindfolded transmission rebuild. Maybe not super hard to do, but it's pretty easy to fail at = mess it up by having one of those copper wires break while surgically removing the epoxy coating.

On my last refurbish I didn't change the slip rings because I just changed the polarity of the brushes instead.

Using heat to remove the epoxy drops the difficulty in half for that part but I broke the very end of the field winding off and had to patch that so it's still risky.

If you aren't well versed in wire/solder repair, stick with brush only fix. (it's not difficult to follow my direction on how to swap polarity and a couple people have reported success doing the procedure).

Ok, reinstalled the alternator, cleaned the MAF. Brake and DSC lights still on and shortly after cranking the Trans. failsafe light comes on.

Lurches into reverse, lurches into drive. Barely moves in first gear in the driveway. Making a bit of a whirring noise in gear.

CEL codes show all four O2’s not functioning dont remember the code #.

Gear lurches have me concerned. I plan on checking the tranny fluid level at the pan. (I replaced the trans filter and fluid several thousand miles ago)

Suggestions? Thanx.


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Dreaded trans. Failsafe prog.
 

Gear lurch is normal if trans failsafe. you need to clear the code from the transmission module.

You also have to confirm your alternator is on putting steady voltage. The symptoms are describing are bad alternator output.

FYI, that can happen easily if you did not tighten the nut
on the alternator. I did that once that’s how I know.

Also if the nut that secures the jumpstart post is loose you’ll get the same symptoms. Shows up about twice a year on xoutpost

Tuned in for a solution. Weird to have MAF, o2, and EGS codes and not have it be electrical (usually alternator as pointed out).

I'd say to check the mechatronics connector at the trans for corrosion or oil intrusion... but don't think that would generate MAF or o2 codes.

I was going to add about the transmission connector. That was the cause of my trans failsafe other when I forgot to tighten the nut on the alternator output. (wow did that connector get hot: it was literally glowing).

I didn't mention because trifecta comes on with no preexisting situation like wheel sensor it's almost always alternator.

Replaced ≠ fixed. I bought a refurbished and it lasted less than 3 drive cycles. Follow the symptoms even if it means reworking a part you just worked on.

Ok, thanks.
I made sure to tighten the alternator cables, will re-check the jumper cable posts.

Looks a bit deeper on my code reader and got a “failed to connect” message for EGS section. 3A is the code.

Along with 16 DME/DDE does not fulfill torque request
17 Coding error (What?)
And
10,02,01,03 No found…..

Likely going to put in an Alt later in the week. Possible the EGS switch is bad?


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Transmission connector was not dirty, but sprayed with deoxit and reconnected. No change….


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Check another thing off the list then...

I'm left with outlier suggestions. You have rodents that might have damaged harnesses leading to the ECU box in the engine bay? Checked fuses in the 3 different fuse boxes?

Maybe your DME failed? It's not common, but not unheard of either. You could check the electronics box it's housed in for corrosion.

Will do. This car lives outdoors so…..Mebbe.


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Is your ABS cable still disconnected? If not, disconnect and clear codes and see if it will stay out of failsafe. I know you disco'd it...but if you didn't clear the codes after disconnecting it...the ABS can still interfere. I'm the guy who had the 4.6 that would go into transfailsafe at 71 mph (and reproducible). I chased gremlins for almost a month until I looked at the Car Area Network diagram and realized the ABS and EGS could speak via the CANbus and DME. I pulled the ABS and cleared the codes and no more Trans Failsafe. Sent my ABS out for repair and all was well once I reinstalled it. Just my experience and would suggest you at least try it out. Best of luck to you! :)

Dreaded trans. Failsafe prog.
 

Thanks, yes I did disconnect for a bit. I’m not sure how to clear the ABS code, is that through the dash diagnostics? My cheap scanner doesn’t have that ability I don’t think. Creator 310+.

I do notice that when I turn the ignition key the brake pedal slumps noticeably more than it used to so you are probably on to something.

Is it the electronic part of the ABS needs rebuilding of the whole damn thing?

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I'm not familiar with that scanner so you'll have to dig in on that. If you don't clear the codes after the disconnection of the ABS, you won't really be able to see the result and determine if the ABS is part of the cause.

I'd highly recommend you purchase a Foxwell NT510/520/530 scanner if you are going to be diagnosing your X5....or install INPA on a Windows 10 laptop which will allow you to scan and to clear as well.

The c 310 from my understanding is a capable scanner, but finding the correct submenu just like with foxwell can be a challenge

Ok, while waiting on parts I had a chance to test some of the fuses and all I tested were fine. These were in the glove box.

5 Alternator
9 Srs
46 transfer case
51 ABS
54 EGS
55 ABS
63 ABS

Oddly, fuse 54 was completely missing? I replaced the 15a fuse but with no effect. I’ve have owned and driven this thing for 3 yrs with no problems but I’m baffled how what seems to be a critical fuse is a) missing b) seems to have no effect.

Current codes (other than Yellow Brake and ABS das lights include

3A no message from EGS control
82 signal,, CAN ASC/DSC
And still all four O2’s

I tried to reset the ABs code and the EGS code but the connection failed on both.

I will be replacing the alternator, the idl control valve ( was occasionally throwing a mechanical failure code) and the MAF sensor soon but frankly not optimistic.

Thanks for every opinion I get.


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Things I’ve learned.

Got into it to day and replaced the Idle Control Valve.
On reassemble I inspected the DISA valve and it’s is broke. (I think). There is 100% slack on the flap so even if it’s getting vacuum it’s not functioning. Ran out of time but will troubleshoot tomorrow.


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Look at my repair thread on my wife’s failed I fixed it for $.18

Failed DISa?


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Dreaded trans. Failsafe prog.
 

Are you asking if I repaired failed DISA for 18¢?

Answer is yes. I'll see if I can find the thread.


https://xoutpost.com/bmw-sav-forums/...disa-20-a.html

Nice! I went the cheap kit route but likely will at least use the Teflon tape strategy.


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Get some fastape brand. It's color changing so you can tell when enough is applied.


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Good idea…

Ok, I have my 03’ 3.0 reassembled but still goes into trans Failsafe. Ending doing a ICV, Testing different MAF, rebuilt DISA, alternator, no effect. Started to re-examine the transmission switch and my old Sears Jack failed on me as I was starting. The timing is not lost on me….still hear my wife’s “be careful” ringing in my ears.

Anyway, my son has claimed he has an INPA laptop but he’s hard to pin down so I may buy a newer code checker. My creator 310+ indicates communication failure when doing ABS/DSC, EGS and anything transmission related.

I’m working my way through symptoms and been through tons of Youtubes looking for the magic bullet.

Thus far I have narrowed to several possibles.

EGs module? Corrosion? Car sits outside and we have had lots of rain. Will try to pull and look for dirty or corroded connections. Some chance a rodent or something damaged a wire. (Popped the hood the other AM and there was a frog on the intake manifold)

Transmission switch? The PRND lights up on the dash but doesn’t change when shifting. Sport mode does not register on the dash. Sport mode shift also seems odd but I don’t ever use it so not sure.

ABS module. Dunno?

Check the trans fluid level.

Wheel sensors and such.

Battery. Replaced the battery with an Autozone cheapy and seems ok (4 months) but I have the one I pulled, may reinstall just for grins.

Most seem to think it’s electrical but so far I’m baffled. I suppose a better scanner would help.

Thanks,
John


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See if you can get into module like HVAC. If you can but not EGS, then get some deoxit pro gold and clean the contacts at the egs module. Your symptoms match bad wiring or bad connector. (or internal fault).

You can open up the EGS and look for corrosion inisde. You may have to drill out rivet I can't remember if it was DME or EGS that wasn't screws. (you can replace with screws).

+1 on some general contact cleaning.

I had symptoms of LCM failure on my e39 530, most likely due to just not driving very much. Went through the process to get a new module, etc. but first I just removed the original one, cleaned the contacts and board with Deoxit, plugged it back in and it's been fine ever since. At least I had a spare.

It sounds counter-intuitive but a good removal and cleaning of contacts once brought back a completely dead old BMW transmission module. Car would not shift, everything lit up, and I simply pulled, cleaned and reinstalled (along with some doing the same on the grounds) and it worked just fine. It's not a bad idea to try.

Thanks, I sprayed Deoxit around (there was zero sign of corrosion) but no help.

Thanks though.


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I'm seen where some module on the same buss shorting out will cause communication errors.

Search for that cause. Look at which / where modules share the same buss.

Also members have had problem where they couldn't connect because the OBD port itself was broken.

Minor update. Raining here so not much I can really do.

My dISA has failed. The flap doesn’t budge with key in pos 2. Getting 12v at the connector but no movement. Looking for a replacement. Wondering if that along could cause electrical glitch? Still getting intermittent all four o2 failure, blessing the DISA is on the same circuit as the MAF.

Idle is fine, drives ok- just around the block.

Dashboard showing PRND but shift position not registering when switching. It used to. Seems to point to a failed position switch?

My scanner locks up when reading anything frommABS or DSC sections. Communication failure.

Was going to check the trans fluid level but my old Sears Jack failed when I got it 1/2 way raised. Scared the crap out of me even though I wasn’t underneath.

Sheesh.


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Have you checked the connector on the back of the transmission?

When mine got filled with water the main symptom was the PRNDL acting odd

Stop talking about my crack... [emoji1787][emoji1787]

Mine had a crack that allowed the block to spread and it was frustrating..!!

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That's hilarious. I was taking about his crack without realizing

I checked the connector on the drivers front of the transmission pan close to the Bowden cable connection. Is there a switch at the rear also?


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Not sure what that connection is. The main connection is starboard aft. At least I remember easy access by driving up onto a curb and using a driveway opening in the curb to roll under the car to shake the water out of the connector. It's a large round bayonet type connector.

Ez on the nautical terms sailor. I’m a land lubber.

But I like the curb cut as an ad hoc quick ramp technique.


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My original thought was to drive straight up onto a curb stop in a parking lot but the car was in trans failsafe so 4th gear made that a very bad idea.

Had to drive around a couple neighborhood blocks until I found an appropriate driveway with a nice tall curb but it worked perfectly.

For no good reason people like to swap which side they call left and right on a car then they use driver side and passenger side but 1/3 the people on xo have RHD so those are not good to use.

We could use gas filler side which is the same I think world wide. (that coincidentally is the right/starboard side, it does not magically become the left side when you face the car from the front).

Point of fact; my right arm stays my right arm when you face me. It's not different with cars, I have no idea why a large percentage of people think it does.

Anyhow i think I climb in right under the right front door to get to the connector but it is so close to center I did it from the left side the first two times.

Ok, take the rest of the day off I’d suggest.
As am I.


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Question: if you put 12v to the DISA , does the flap shut?

Just got a new DISA and it doesn’t move with 12v applied to it. I see a YouTube where if you put 12v to it the flap slams shut.


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Dreaded trans. Failsafe prog.
 

No. You suck on the hose fitting. It's moved from vaccum that is controlled by the solenoid.

If you look for my repair thread on disa (search andrewwynn and thread disa) there is a pic of me testing the vaccum motor

Tranny fluid question.

I got around to checking the trans fluid level and cold when I crack the side flung plug and a significant amount of fluid came out, probably a cup and a half before I replaced the plug (and more would have come out.)

Assume the fluid was changed at some point? Isn’t it supposed to be topped off the point where the fluid no longer leaks out when running?

If it’s not at operating temp, make a difference?

Perhaps overfilled or am I’m looking at it wrong?


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Has to be warm but also maybe running? Running would take up fluid that is clinging to moving parts so I wouldn't presume it was over filled unless you are supposed to fill with it warm but off (fluid expands when warm).

Too busy to look up the procedure I just remember warm like 130f=54c

No longer leaks when running warm (40c IIRC).

Although, if the trans has been running and you ran through the gears, fluid shouldn't be coming out when it's cold either since the fluid expands when warm.

You don't mention it, but the car was running when you did this right? If you do this with the car off you will lose a lot of fluid.

But yes it's possible it's overfilled. Start the car and run through the gears (a few sec in each gear). Then put the car in P, and using a IR thermometer or a scan tool, monitor trans temp. Pull the full plug and either fill (or drain) until there is a very light amount of fluid coming out when the trans is at about 40c.

Don't pull the drain plug!!! :confused:

I think he meant pull the fill plug, and either fill (if under filled) or drain (if over filled) through the fill plug.

The X definitely needs to be started or you will lose a lot of fluid out of the fill plug. I only know the procedure for the ZF trans, but assume the GM trans is similar. Must be filled warm and running. Final fill between 40c and 50c. Again, that's ZF trans. Have no experience with the GM trans.

Yes that's what I meant!

Procedure for GM trans is the same (although the fluid is different)

Help with some terms please?

The EGS (electronic gear selector)is the blue trimed electronic box under the right side wiper blade area? Is it also called the TCM (transmission control module)?

I have a GM trans. Part number 7 518 603 (not sure the tag will be visible in this post) does this have a more common part description as appears in the manual?


Thanks




https://uploads.tapatalk-cdn.com/202...541f95bb6a.jpg


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Dreaded trans. Failsafe prog.
 

Ok, got to the heart of the matter. I pulled the engine electronics fuse carrier ( underneath the right side windshield wiper and in a box with the TCM and the ECM). The 30A fuse in slot four was burnt.

Fuse 4 is Automatic transmission control module (AGS) (A7000)
And the oxygen sensors heaters. (I got getting an Oxygen sensor code also so that is confirming.

Replaced the fuse…..no joy. I’m going to recheck it but on first check after startup, the fuse was good. Have drive 10 miles since so worth a check. (Drive reasonably normally)

Does this indicate a bad TCM or something short in the trans? Or something else entirely?

One other symptom. On startup the P of PRND is brightly lit but shortly goes to dim as the other 3 letters.

Thanks.


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Fixer was having a similar issue. His blew the fuse up front and it was because of his O2 sensor wiring shorting. He posted about it on the E53 forum. You should probably check your wiring as well.

He saw the post but good looking out


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Fuses blow from a short or power surge to keep the system from frying. If you replaced the fuse but still have the same errors then possibly tcm damaged, but I would check all related wiring first. If there's still a short somewhere you'll pop that fuse again. But if the wires burnt through you'll have an open circuit and no power to the tcm... if it's the tcm harness. If it's the o2 harness you'll just get an open in the o2 circuit.

Is the tranny shifting though? My tranny lights are dim too, but I've got full function. Sport and manual mode works just fine.

Dreaded trans. Failsafe prog.
 

Thanks. I went through the O2 wiring this am and all looks good. I don’t exactly know how to test the continuity on the O2s but am checking in the manual to find the O2 power connectors. I did disconnect both upstream 02’s and started the car and yet another fuse blew. Not a good test but that somewhat tells me the O2’s are not the problem but still tracing.

I did reclean and reconnect the TCM wiring, blew the fuse again. I suspect the TCM is the culprit. Haven’t found the trick to remove it from the container but I trust that I’ll figure it out.

I did notice that one of the harness connectors to the TCM contained a few wires that apparently had either been spliced or repaired as evidence of clear shrink tubing. Normal?


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The spliced in looking wires are normal.

You need to follow those o2 wires to the dme. Pre and post wires. The short could be before where the wires disconnect. Mine was. Buried close towards the firewall on the edge of the back exhaust header.

TCM comes out pretty easy. There's little plastic clippy things that you press on so you can slide it out.

I have a couple spare tcms. 30 bucks plus shipping if you do need one. You can code it with pa soft.

I really doubt the tcm is bad though.

Thanks. So your short was near the TCM? The O2’s are on a harness connector that plugs in to the TCM?


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My short was near the back of the valve cover. The wire harness was laying on the exhaust manifold. It burned through.

https://youtu.be/funoO_3PTeU

There are 4 o2 wiring runs. They go to the dme. But power is supplied through that fuse that is also supplying the egs. Aka....tcm

Actually it's the voltage for lambda sensor heating (all four) which comes from that E-box fuse F4 and also to EGS (TCM as you call it). A wire from that fuse and wires to those loads are connected together (X6962) and bundled in the E-box wiring. So they are not connected to DME. So if you want to investigate the cause of that burning fuse you can separate the wires (red/white) from that bundle and measure which one is shorted. As you can see in that diagram the lambda sensor heating has 0,5 mm2 wires and both supply wires to EGS are 1,5 mm2.

https://bmwteka.com/wds/en/e53/57056cbb

Awesome.... thanks for clarification.

It also goes to my aftermarket angel eyes [emoji6]


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Thanks very much.
So, the red/ white stripe wire from the f4 fuse is shorting? Measure continuity and resistance from the male pins at the O2 connectors? Will it display voltage with the key in pos2? Not crazy about starting the car with me laying under it.

Do the downstream O2’s have the same connectors, not seeing any?

I have 3 of the 4 O2’s disconnected, fuse 4 still blows.


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Measure from the red/white to ground. It will be a pretty low resistance though the four O2 heaters. Unplug them all and then you should get a fairly normal resistance. O2 heater is about 2 Ω which is practically a short. 12/.5=24A from all four.

The connectors for post cat sensors are both on top of the motor the pre cat are above the exhaust manifold. Keep track which came from where with some tape etc.

Dreaded trans. Failsafe prog.
 

The pre-cats are right in front of me but can’t seem to locate the downstream connectors. Are you saying they are likely in keepers on the rear behind the intake or valve cover?


Ok, I just figured out they are under the vanity cover. Duh.


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They are clipped on top between the valve cover and the intake manifold. Under the beauty panel.

https://www.pelicanparts.com/BMW/tec...mall/pic07.jpg

Thanks, beat me too it…..


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Minor update: looks as if someone changed the downstream O2 (or at least one) as one of the connectors was missing from under the vanity cover. Just laying on the back of the engine . Cable heat tube was heavily frayed either from heat or critter chewing but so far no sign of short or damaged wire.

Ran out of time, back at it tomorrow.


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Unplug the damaged wire and see if they fuse doesn’t blow

Well, I tried the unplug thing. No joy. I have now unplugged all 4 O2’s individually resulting in 4 dead fuses……

I’m going to have to test for continuity at the connectors and hope that the short is somewhere accessible.

I suppose it’s possible the TCM module has the short? Any advice on testing that that can be done with a multimeter.

For clarity, the fuse blows in Key Pos 2 not started.
Once started the data stream shows both down stream O2’s getting voltage, neither upstream. Odd, since the fuse connects to all 4.


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Plug all 4 o2's back in and unplug the TCM and see if the fuse blows in pos 2?

The o2 sensors "produce" a signal voltage they don't "get" voltage. The voltage supplies only the o2 heaters to get them "producing" a voltage faster as they need to be hot to work . Are you saying that the fuse doesn't blow until you connect any one of the 4 O2 sensors??

I think he says fuse blows when zero O₂ plugged in. You need to unplug the TCM (EGS) and you can meausure the wire squid to ground vs. Blow fuses to test.

Four O₂ heater will look like a short on a DMM so leave those unplugged. Unplug the EGS and see if the wire is shorted before putting in a new fuse.

The egs can be opened to check for a mechanical short eg: pin to chassis. I can't remember if egs or DME needed to be drilled open. One uses rivets but a simple machine screw can replace the rivet.


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There's definitely a short somewhere popping that fuse. Whether the o2 runs are connected together or not doesn't make a difference. Just means the short is on the harness before the connections. Which means a little harder to find.

Somewhere you have wires touching each other or shorting to ground making that fuse pop. I would be very surprised if the egs is shorted. That said, unplug the egs and see if the fuse still pops. If it does, it's not the egs.

Thanks all.
Question: there are two in the box, the EGS(TCM) is the one closest to the front or closer to the rear?

I put my DIMM in the fuse box attached to one lef fuse location 4 (no fuse) and tested continuity at the O2 connectors. Upstream all tested good, down stream all open. Switched to the other fuse 4 connector and same thing. All up good, all down open.

Oddly when I used my scanner to to data stream the up stream was not active (both banks) the the down stream was .99v if I remember correctly.

As it looks like at least one of the O2’s was swapped previously, is there away to determine (other than it just seems to be the right fit) which sensor goes to which connector? Are both up and downstream heated?


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The blue connectors are the egs.

The black connectors are the dme.

I unplug one O₂ and check which one is stuck at .43v. That's the unplugged one. The one that doesn't reach as far is back l bank two.

Disconnected all EGS connectors, still blew a fuse in Pos 2. Didn’t have time to test anything else but will start short testing the heater wires (redWS) tomorrow.
thanks all


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Well.... the module is good then. I'll see if I can make a vid for you of my disaster..... it's nuts what I found.

That's prob very good news. Much better to have a short in the wiring vs. the module


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Here's a vid of where mine were broken. Not sure if it will be helpful.

https://youtu.be/3sD1Jh_b1Wc

Thank you very much. Very much!

I’m gonna have to dive in today. I’m “husky” too so….wish me luck.

My understanding is the voltage is only present at the O2 heater circuit? Red/wS. That true?

Thanks again.

John


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My understanding is five wires are tied together with a crimp connector in the e-box.

I would cut the connector out to find which of the five are shorted. You already disconnected the devices narrowing the short to a wire. Find out which wire by measuring each of the five (six including the feed) to ground.

They should all be open ckt including the feed if the fuse is blown.

It should save a bunch of headache if you can root out the exact wire.

You can also continuity test each individual wire to the O₂ connectors to figure out exactly which goes where.

It's just as likely the feed is shorted that's why I recommend cutting out that splice and measure each wire separately.

Anything that instantly blows a 30a will show up on a DMM.

12v/30a = 0.4 Ω. A meter will show 0.2 Ω on just the leads so you should get a reading below an ohm.

You already unplugged all the connectors your short won't be under the car. It should be in the ebox, in the giant harness by the firewall or bewteen the 30a fuse and that 6-wire? bundle that combines output of the 30a fuse to the egs and O₂ heaters.


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Actually it's 7 red/white wires connected together: (like shown on the diagram I linked on my previous post)
*1x 1,5 mm2 supply from fuse F4
*4x 0,5 mm2 lambda heating
*2x 1,5 mm2 EGS

https://bmwteka.com/wds/en/e53/57056cbb

I think this is the guy who did his own head gasket so the harness is probably pinched or damaged behind the cylinder head/valve cover. Might be wise to check for something obvious before getting into the Ebox and cutting wires.

Under my car were splices that were melted. PO did a great hack job. Harness just laying on the exhaust.

Doesn't hurt to make sure it's good under there.

:iagree:

This, because I almost pinched those harnesses under my valve cover on my e46 doing the m56 valve cover mod. Very easy to screw up that way if not paying attention.

Yes makes sense to see if that main harness got pinched. The "cutting wires" is 2/10 difficulty since they are already terminated in a crimp terminal. If you cut of the terminal careful with a Dremel or sharp small diagonal cutter you won't even have to strip any wires to reassemble.


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Thanks all. I was thinking about pulling the valve cover today, and may still but I don’t suspect that’s the problem. Oddly, all of the O2 wires appear sound and rubber insulator still good. One of the downstream ones has a good bit of the rubber insulator torn so I stripped a good bit of it off expecting an obvious break or shorted spot. Found none.

I connected my Multimeter with the red probe in the hot side of the fuse 4 slot and the O2 harness and got 12v on pins 1 and 3 and something like 7.5v on pins 2 and 4 with key in pod 2. Both banks. ( pins have no real reference point but it simply was every other one was 12v)

Not sure this proves or disproves anything but it was my understanding that only one of the 4 O2 wires (red/ws heater) received voltage.

Of course it started raining and the car is outside….


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Mention of a 6-wire connector or possible a 7 wire from the wiring diagram. Possible this is all on one bus (connector) that can be unplugged to test for continuity?


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No need to remove the valve cover unless it's pinched on the harness.

You should check the harness from the back of engine over to the eBox

An endoscope or inspection camera comes in handy for these sort of tasks.

Yes, it does. I have one.... can't believe I forgot i did. I buried it away after I used it last year.

Fairly inexpensive on Amazon. Used one on my n54 when it shredded a belt. Those are notorious for pulling the belt into the oil pan through the crank.

Came in handy to look inside my oil pan.

Definitely will be handy to look in the tight spaces where Those harnesses run.

Good idea, I have a cheap one, always glitchy. Will retry.

I’m not sure visual inspection will get me where I need to go as these O2 wires are wrapped in a rubberized shroud but one shroud definitely has been partially removed either heat or critter damaged.


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Well, I guess I’m going to have to tear into the O2 sensor wiring and look for a short. Appears from continuity test that the Dow streams are not getting current but oddly when I hook my OBd 2 scanner up they transmit data but not the upstream. And both are not functioning.

I really don’t won’t to tear into the harness past the rear of the engine as it seems damn near possible I could get a wire back where it needs to should I even find a short.

Studying the Bentley diagram shows that red/ws feeds power to the O2 Heater all4 wires. With a brown, yellow and black wiring going to the DME.
I’m confused by the block diagram, I assume the .5 is the wire size?
The numbers next to the wires, are those PIN numbers? I also see what looks like a fuse 5v(15) inside a6000 DME? I would assume if there is a DME fuse inside there would only be one and the car would be dead.

Likely I’m over complicating this and it’s something simple right in front of me…..

On the verge of taking to an Indy but still being stubborn (and trying to learn something in the process)


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https://uploads.tapatalk-cdn.com/202...39b27ea79f.jpg


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That's not a fuse symbol on the DME block - it's a resistor. The resistor and transistor symbols simply indicate an actively controlled input or output on the DME module, nothing more.

In this case the O2 sensor has +5v (voltage) on one side of the sensor element, via a current limiting resistor (most likely).

Got it, thanks.


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Ok so my helpful neighbor brought over one of those power probe knockoffs to try to isolate the short. My question is if I bypass the fuse that blows and inject 12v into the Red/white stripe wire will I a) damage anything? B) learn anything?

The probe has a circuit breaker so I’m slightly comfortable but not completely.
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If it has ckt breaker nope won't learn.

Almost certainly just one of the six wire runs is shorted. It literally takes 20 seconds to crimp them back together, cut the crimp off, measure each power to ground and find the short then trace the shorted wire to find the fault.

Didn't you say when everything unplugged still blew the fuse?

Actually, that tester might work better than DMM for testing the short however. Once the lines are isolated. However with the O₂ unplugged the lines will read open ckt unless fault exists.

A yellow butt splice should work to connect everything back up. Blue maybe and put half in each side (electrons can make a u-turn it's not like plumbing where corners slow it down)

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Ok, thanks. I pretty daunted by tearing into the wiring bundle. I don’t mind cutting and butt splicing near the fuse connection but I guess it makes more sense to peel the heatshrink off the suspect O2 wires that I can actually see before trying to find a short in a packed in bundle that would be nearly impossible for me to fix without taking half the firewall apart.

Also, not sure your last paragraph, unpack that for me please?
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If I remember correctly the crimp is an end splice with all the wires going into one side. Those are more rare; it is easier to get butt splices and you can split up half of the wires in each side. My point is you can use either.

If you have a Power Probe, you can feed power to each line on the O2 sensor circuit. You have the TCM removed, and the 02 sensors removed then no reason not to feed power to each wire and see which one trips the breaker.

Or you could simply get a test light and see which wire provides the ground to turn the light on?

You have to cut them apart to do that test.

If any wire is grounded they are all grounded through the common splice.

Maybe I missed it but all 4 share common power?

I’m not certain but the red/white stripe wire that gets power from the f4 fuse provides power to the heater circuit on each of 4 O2’s. But at the F4 fuse box there is only one wire that runs out of the EBox into a wire bundle wrapped with waterproofing through a finned plastic conduit then breaks into 4 red/ws lines and 4 black rounds for the 4 O2’s.

If the short is somehow inside the wrapped wire bundle or the conduit will be beyond my meager skill and physical reach to replace a wire(s). Sure hoping the short is from the rear of the engine forward or I’m gonna have to send it out.

Been pouring over the Bentley electrical diagrams hoping there is some sort of relay or other fuse that makes it appear there is a short but so far nothing.


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On my car, the split of the main feed is visible inside the ebox. That connector is a crimped connector and can/should be cut apart to determine where the fault lies.

As long as they are all connected you can't tell without visual tracing the entire wire where the short is

I’ll look for that. Thanks.


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So I totally believe all this but then how the HECK does the ECU know the voltage at each O2 sensor??

The resistance of the sensor and ECM after very very high in relation to the wires going to/from the sensor such that the wires are negligible.

The O₂ sensor generates a voltage based on the relative O₂ content of the air inisde the exhaust and the reference sample of O₂ in the wire lead coming into the sensor outside the exhaust.

That voltage travels down the lead wires at nearly instantaneous speed: roughly 180,000 miles per hour or 1/3600 the speed of light. It's effectively inside the ECU electrically.

The wires in question are not the sensor wires they are the heater power leads.

The heater power is always active when the key is on (and up to a few minutes after the key is off). The heaters are controlled with PWM control of their respective ground paths.

I believe that is true so I’m only looking at the red/ws wires coming to the 4 wire connectors to the O2 leads. A little earlier you referenced a “main feed” that is a crimped connector? When looking for that will that be immediately emerging from the 5 fuse holder at fuse 4 or somewhere down stream?

Thanks.


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I can't remember where that splice was but it should be close to the fuse. I thought you already identified it.

Where about seven wires are crimped together, two of which go to EGS, four to the O₂ heaters. That needs to be cut apart. If you cut through the crimp with a Dremel you can avoid having to try to strip the wires to reattach later. There might not be enough wire to do that without difficulty.

You cannot determine which of the wires is shorted when they are all connected.

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FWIW this is the 09/03 model so apparently there were some changes made in that production month as referenced by the Bentley manual. https://uploads.tapatalk-cdn.com/202...9121c96ef8.jpg

This picture shows a few crimped wires at the AGS but these are the only crimps I have been able to find.
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https://uploads.tapatalk-cdn.com/202...345ae54b7c.jpg

This connector pulled from the AGS has 2 red/white stripe wires and displays continuity to the red/ws connectors on both banks of upstream O2 pin connectors. Also on the black wire pins.

No continuity to anything on the downstream side.


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https://uploads.tapatalk-cdn.com/202...46ccb018c6.jpg
Trace those two wires they should mate up with the four O₂ heaters


If those are the red/white hot to the EGS. They look brown/white maybe in photo

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Two in the foreground are red/white stripe.
Only a few inches from this connector the wires disappear into a larger wire bundle wrapped in black tape that all goes into a plastic conduit. I guess I have to either disassemble the black tape and locate the splice or peal off the sheath of the suspect O2 wires and look for a shorted wire.

FYI it get continuity on both upstream wires (zero on downstream) at this connector as well as continuity to chassis ground in 4 of the six connecting points.


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Take off the tape e hand had to remove that before I found that splice. I am pretty certain it was in the e-box right before going into the plastic conduit behind the engine against the firewall.

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I took the crimp out where the two larger dia red/ws crimp to the 4 smaller dia red/ws heater wires and got continuity all 4 corners so sorta ruling out a shorted wire except maybe the crimp was bad. Doubt it. Probably put a little solder on the 6 wires before re-crimping to make a surer connection.

Also, pulled the AGS brain to check for broken or bent pins. Looks like it is held together by tabs on 4 sides. Dare I Jimmy it apart or leave well enough alone?
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Explain "got continuity". When disconnected you aren't supposed to get any Reading. When unplugging the O₂ sensors the wires should all read open.


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Took the red/ws crimp apart, tested continuity on each line and all good. Re crimped, blew the fuse….

Not surprised.

Will test the other wires coming off the same bus but out of time today.

Sheesh.


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Separate the red/white wires from the common point and measure each one separately for resistance against ground. If the end loads (lambda sensors and EGS connector) are removed the resistance against ground should be infinite. If the end loads are connected the resistance should be above ~2 ohm. If the resistance on some wire is lower indicating a short to ground separate that wire and connect all the other wires back together and install a new fuse.

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I think I’m close. Did Resistance test you and Andrew Wynn suggested. Cut the crimp, separated the red/wS wires and read resistance all OL except one. Of course my DIMM battery died in the process and it got dark so back at it tomorrow. Likely an up stream wire crossed the exhaust manifold but haven’t isolated it yet.

Re-reading your suggestion with the O2’s connected should not read OL? But with O2 pigtails disconnected OL is correct?


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Reading with O₂ connected doesn't mean anything. You will probably get some resistance value but it's though the DME not helpful.

If you found any that read not OL that's the job you were tasked to perform.

It sounded like it would be an upstream sensor maybe melted to exhaust manifold. You are very close to solution.

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Ok, progress. As expected/predicted when I pulled back the sheath on the bank one, upstream O2 part of the 4 wires were fused and shorted (likely got too close to the exhaust manifold. Gonna butt splice all 4 wires or figure out some way to peal them apart without breaking them, reassemble the rest and hope that ends the ordeal. I’ll post back after I get there, probably inspect bank two to be sure that aren’t suffering similar fate.


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Yep, that'll cause a short. Nice you found it in what looks to be a serviceable space.

Lucky about that, kinda right in front of me. Might solder splice and heat shrink so I can hide my handiwork under the sheath…..


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Use these.
https://americanclipsandconnectors.c...r-sleeves-blue

Makes for a clean repair. Then heat shrink over that.

Those wires look more like they got crushed than melted.

Possibly a combination. At some point those might have been pinched by a valve cover or something.

They were sorta melted together so when I separated them they distorted. Right in the area that could have laid on the exhaust.

These are .5mm wires, I will replace most of the red/ws and splice a few inches of the 3 others. The parts stores near me have 18 gauge that is slightly larger than .5mm. I have some salvage parts from an e46 with .5 mm wire for the yellow, black and brown wires( not the same colors but wouldn’t think it would matter) but will be running at least 2 feet of red wire to 12v. Will 18 gauge work instead of .5mm?


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Is there not enough slack to just splice them together again? There is usually a good amount of length on the O2 sensor side. Reason I say this is that 1 splice is better than 2 :)

Thought about that, I need to get a closer look for damage. Concerned that an O2 wire needs to be stout or the readings will be off and cause a CEL.


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18 gauge should be fine though 24awg wire would be more size appropriate. Splice with the 24 awg wire might look better too. The solder/connection quality will be more important than a slightly larger wire. Be sure to get some acid flux or something for good solder penetration/coating.

Go to the junk yard. Cut the 02 sensor runs off pretty much any bmw with the m54b30 motor. You'll have enough of the same correct size wire of the correct color.

Those really aren't great to use in places that see heat. The solder can heat up, reflow, and have the wires separate.

I'm a fan of butt connectors with no insulation over them. They're very slim and when covered with heatshrink line with adhesive, they're water proof.

Lots of OEs supply those connectors in their wire repair kits. I haven't seen any that supply those solder melt butts.

Where do you find the no shield butt connectors?
I may go to a boneyard but closest is about a 2 hr round trip. I may just try to get it back on the road and when It’s convenient, fix it correctly. It only gets about 2-3kmiles a yr now.


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You can get them on Amazon

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Lifetime supply:

https://www.homedepot.com/p/Tyco-Ele...-000/205878599

Single sided like I think the OE style is.

I'm very excited to see this fixed!

Ended up soldering a combo of the original wires and some 22 gauge wire I had from a stray part. Ran out of flux and time so maybe tomorrow if I can find some flux.

Funny thing, I wanted to take the wires off a junkyard car, just snip and crimp or solder and the two BMW boneyards I spoke to counter-offered that I could buy the entire wiring harness for $400-450 and cut off what I needed. Funny.


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Don't reattach anything until you find the short. Did I miss you finding the short?


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Yes, like you thought about midway between bank 1 and 2 most of the 4 wires had fused together from heat about an inch. The bank one upstream was shorting. I cut out the damaged parts and soldered pieces of same size wire as the four wires but ran out of flux and had other stuff come up before finishing. Oddly, no local stores sell electronic flux……tried to get a cell phone guy to sell me some but had to order from AmAzon.

I will test all the connections prior to giving it 12v.


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Ok, progress.

Reconnected all the wires. Soldered some, butt connected others. Tested the connections. All good.

Fired it up, Trans is good, O2’s good. Still have ABS, DSC lights on but for another day.

Not entirely happy with the wiring runs so I will likely redo a little of it but calling it done.

Thanks for all the help and patience. A good time was had.


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Abs won't clear until you drive clear all codes and double check LEW module (separate module for only the steering angle sensitive m sensor). You have to clear sas error though that module.

Yeah... the lew probably needs a recalibrate. You'll see when you run inpa or PA soft what is causing it.

My Christmas lights were due to a worn out transfer case motor gear. Cheap plastic that gets chewed up real easy. I bought a brass one to replace it.

https://www.autohausaz.com/pn/UR-27102413711PRM

Then also oil abrasion. Just change your transfer case fluid. To clear that one though you need ista.

Or foxwell scanner.


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Update 2: dressed up a couple of wires I wasn’t satisfied with, put all the wires where they belong off the exhaust manifolds.

Fired it up, ran fine, no CEL, drove about 30 ft and the ABS/DSC/bRAKE lights went out.

Happy as crap!

Thanks all.


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Well that's just fantastic news


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Awesome news!!!
[emoji3060][emoji3060][emoji3060]

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