Transmission fail safe..
 

Recently the trans in my 02 4.4 has been not shifting up to 3rd. Didn’t do it all the time only occasionally.
Today it pinged and I got ‘trans failsafe’ readout on the dash. No other lights ie trifecta but it’s stuck in 3rd gear.
Scanned it with my C110 and it says-
‘DD CAN timeout ASC/DSC’ and
‘DC CAN timeout, electronic transmission management (EGS/AGS)’.
Can anyone shed any light on this?

Happened to me when water got into the connector at the back of the transmission.

Ooo. Interesting. I'll go home a check it..

Nope it's not that

The error suggests a problem on the communication line but also mentioned DSC yet no trifecta.

Is there a second wiring harness that goes to the transmission? Else check the other side of the cable where it plugs into the control module in the e-box under the hood.

There is only one big plug connector at the bell housing end of the transmission. Nothing else. It’s a ZF5hp24.
I have a gut feeling that one of the internal solenoids has failed / stuck but could be wrong.
It was rebuilt 2 1/2 years ago with a 12 month/ 12,000 mile warranty and I’ve been in touch with the place that did it. He’s happy to run a diagnostic on it and go from there but I’m running out of time.. Flying out of London later this evening for 10 days.
Thinking of the warranty- I’m not sure I’ve even done 12k since rebuild. I must check. That would be a result.

Had the similar codes and failsafe mode when my DSC module failed. However I also had the Trifecta, which I assume you don’t?

No trifecta.

With the foxwell you can monitor all the solenoids in the trans. You can also monitor the "L" lines that tell the car what gear you're in. That was the fault in my case.

Too late. I'm at Gatwick airport. It will have to wait. It's logistics that's the problem - I have to get it to the trans shop which is about 10 miles away which is oy open Monday to Friday when I happen to be busy working..
I may see if I can find someone who does mobile diagnostic to at least give me a head start.
Funny thing is that I've been considering buying a spare car so I could take the X5 off the road for a bit to tinker with it. May do some online shopping while I'm abroad.. Another X5, Porsche Cayenne maybe.... ��

Wet bought two nearly identical e53 X5. We used them both as daily but it was exceedingly helpful to have a "spare parts" host at times. Pulled parts more than once to make one operational. Also as one was older I got to practice a repair on one that I would be able to fix faster on the second go.

Further to my trans failsafe program..
I took the car to the transmission specialist who rebuilt the unit.

I drove the car for about 1 1/2 miles absolutely fine. No problem whatsoever until I had stopped and turned the engine off when I dropped the daughter off.

Upon restarting it went into failsafe mode which also included failure of all the instruments on the cluster apart from the fuel gauge. The temp gauge was all the way over the hot side. No speedo and no rev counter.
I maybe mistaken (due to my heater blower fault - see other thread) but the HVAC didn’t seem to respond when I fiddled with the ‘-‘ and ‘+’ for the fan either.
Everything else seemed to be working ie lights, radio, steering and seat auto wheel adjustment (I have the comfort option).

Anyway, Ian at the garage plugged in the diagnostic machine to see what’s what and all that came up were 3 modules to read. He said that there should be lots more on the display which suggests ( to him anyway) a wiring fault or body control module fault but he did say that he is an expert on transmissions, not electronics.

Thoughts or experience anyone?

What 3 modules?

I would point out that the cost of a foxwell nt-510 that can stay in the car without issue (60c here) should be just fine there and then you'd have the ability to check right away without hoping that the fault repeats for your indie...

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I don’t know what 3 modules. I should have took a screenshot.. Someone on Bimmerforum uk mentioned that if the temp gauge is all the way over in red it means that there is no data from the ecu. Apparently.

Is Fuse 1 okay in this fuse block? It powers the engine & transmission ECUs. (This is actually off a L322 Range Rover, but I assume the E53 is the same).

https://hosting.photobucket.com/albu...080&fit=bounds
https://hosting.photobucket.com/albu...080&fit=bounds

I had similar symptoms on my L322 when the thermostat heater shorted.

https://www.rangerovers.net/threads/...4/#post-421594

Phil

I’ll take a look when it stops raining.. The engine is running ok - starts ok too. It’s just the other things mentioned above.
On a side note - could my hvac system cause this as I’ve noticed that although the blower motor is groaning it sometimes doesn’t run like it’s stuck or something.
Just thinking out loud.

Ok, so I’ve not checked those fuses yet as it’s raining all the time. I have however, scanned the car when it was cold before starting. Only the ignition was on.
This time-
DD CAN timeout ASC/DSC
DC CAN timeout, electronic transmission management (EGS/AGS)
78 signal, vehicle speed
80 CAN BUS monitoring
82 CAN ABS/DSC signal
81 CAN timeout DME
20 wheel speed sensor front right transmits no signals
21 wheel speed sensor front left transmits no signals
68 steering angle sensor internal

Some of those may be explained as the car was stationary I’m not sure.
I took it for a drive for 30 min and it drove ok.
The heater blower motor would not work at all and the hill decent switch was illuminated and would not turn off.
No lights on the dash.
During the drive I reconnected my scanner but it would not communicate with the car at all.
Got home and switched off. When I restarted it was in trans failsafe mode with no speedo or rev counter and the temp gauge was right over in the red again.
Something is going on that I can’t figure out.
Anyone around the globe got any ideas?

Seems you have a lot of wiring issues. Was this car ever in a flood situation?

I would pull all the connections off on the ebox and clean them with contact spray and reassemble.

I think there's a tie to can buss on the oil sensor known to short and cause problems. (not sure if it's that sensor. I had a problem in that neck of the woods once but it ended being something else so I didn't need to swap the oil sensor).

So many of those symptoms are identical to those I had when my DSC module failed. Perhaps your model hasn’t failed (hence no trifecta), but there is a communication issue to/from it with a harness or connector?

My AC and blower were dead
My speedometer was dead
Transmission failsaife mode activated
Almost all of the same timeout codes were present
Pegged temp gauge
Strangely, my aftermarket backup camera that I installed stopped working. I’m assuming because the circuit/fuse I tapped off of in the trunk went dead

It would run fine for a few miles and then all the above would appear, presumably as it warmed up and something shorted internally. I didn’t have the wheel speed sensor codes though. Long odds that they both would fail at the same time. I’m still thinking your DSC module or wiring harness is failing.

I had no luck with eBay modules and had to buy a new one. Fortunately they are still available, but not cheap. Hopefully you can find an x5 or two in a junk yard and yank the modules. If in fact it ends up being the DSC module.

No it’s never been in a flood.
The climate controls still light up and the led fan speed bar goes up and down but nothing from the fan.
I also noticed that when I switch the ac on and off I couldn’t detect the compressor kicking on or off and altering the rpms.
I think I need an expert..
Cambridge Uk anyone..?

Right.
Tonight I’ve taken every fuse out to check and they are all ok.
Headlight removed to get to the ABS unit so I could unplug the cable, check and refit. I took out the ecu from the base of the windscreen, unplugged everything and refitted. The 30a fuses were also checked. The only one I haven’t done is the transmission module behind the glovebox which I will tomorrow.
As far as I could see everything looks clean and dry - brand new looking.
I’ve stuck the ctek on it until tomorrow when I’ll rescan it and run it again.
Anyone got any other ideas…

Today, this CAN video popped up on my play list
Interesting info on how DME, ABS, and trans module communicate. Time for a DVM and oscilloscope.

Looks interesting. I’ll watch it later.
Mine is definitely something breaking down when the car warms up. Three times now I’ve ran it from cold for circa 30 min then it all goes wrong..

Transmission fail safe..
 

I would try unplugging the abs module and see if you can drive without getting failsafe. The time delay is symptom of how intermittent abs module will trip the trifecta. I'm guessing a can buss may be connected to the abs module and is getting shorted when heat gets into the abs module.

Not sure if the speedo will work when it's unplugged and I wouldn't drive more than 100km with it unplugged might get a tamper dot.

I wasn't sure if I could drive with the abs module unplugged. It did cross my mind.
It's uncanny that the above video has exactly the same symptoms as mine and I did have the abs module pack up on my old E39 years ago although that had the trifecta lights on whereas mine doesn't.

Latest. Had an auto electrician out today. The only module that wouldn’t communicate was the abs module according to him so that could be the culprit.
I’ll have to remove it and get it sent off for test poss repair.

Out of curiosity, did he check network communication to the ABS module?

You know what - I actually thought I was wasting his time. I’ve used him before and he seemed ok but this time I had a negative feeling if you know what I mean.
I left him to it but he was only here 40 mins and he was fannying around with the ignition switch and whatever but I did see that his diagnostic did not communicate with the abs but it did with everything else. If I was the sparky I would have probed the abs module connections and done a thorough job to confirm but that’s just me. It only cost me £60 so it’s not the end of the world.
All the evidence points to the abs module and it’s off now and being collected tomorrow to be tested (£45) and if it’s faulty then it’s £200 to be repaired with a lifetime warranty.
Do they just say it’s faulty? Who knows.. Problem is that I don’t want to just keep chucking cash at it to find the fault - the wife is already questioning my logic. Her opinion is that if a car has a problem just sell it and buy a new one..

Fix it = few hundred quid....

But a new one = rather more than a few hundred quid....

What was that comment about logic? ;)

False data can take you down a rabbit hole. Interesting video on how "live data" can mislead you. A network check plus power/grounds checks can save time and money.

Agreed. £40 for the ABS module to be tested and since I had one fail on an E39 and a mini one I thought I would get it checked. If it’s not that then I’m not sure what to do.
I have seen videos on how to check the network with a multimeter via the diagnostic socket but I’m not an expert so we will see.

Update.
The ECU testing company called today. The module was faulty but is beyond repair apparently as it has an internal hardware fault or something so they are sending it back. £19.
So I’ve had to source one off eBay and hope it’s ok. I did that with my E39 10 years ago and it fixed it so fingers crossed.