Some codes I'm receiving in 01' 3.0 5spd
 

Ok so I'm getting the P0141 oxygen sensor code quite often now. It seems to happen if the let the truck idle too long. How do I tell which sensor to replace iirc it system 1 bank 2
Now some others are p0171, 0174, 1349. Once I clear them truck runs fine. I usually clear them on the fly.

My main question is if j replace the o2 sensor should this resolve all problems. Now I also know the battery plays a huge role in these trucks and probability on that ?


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The code P0141 means that there is a problem with the heater element circuit of the heated oxygen sensor. The control module monitors how long it take the sensor to warm up and start sending an adequate signal. The code is triggered when the sensor is taking too long to warm up. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors. If the sensor and connector are OK, replacing the O2 Sensor 1 usually takes care of the problem

P1349 is an engine misfire code and normally have a fuel shut off.

P0171 and P0174 are lean mixture codes which could cause an engine misfire.

There are plenty of write ups on the P0171 and P0174 codes on this forum. I suggest you do a search.

Thank you


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With the misfire codes I would look into replacing spark plugs if those are originals, the lean running and misfire could ALSO be a ripped intake elbow boot, i'm sure you must have heard of the known problem with the M54, its an E46 problem too.

The intake boot is 15 bucks from dealer and OEM NGK plugs are 40 dollars, after you fix your O2 sensor issue I'd look into those two.

I have this same problem. On my X, which coincidentally (or not) is also an '01 5-speed 3.0, it's intermittent. Some days I have no codes and the CEL stays off for long periods of time. Some days I get one or two codes for O2 sensor heater circuit (usually bank 2) and it drives fine. Yesterday the light was off, then I was sitting at a stop light and it started to idle rough, and the CEL came on immediately. I pulled over, scanned it, and it came back with three codes for O2 sensor (one that said no input detected from O2 sensor), and two misfire codes. Turned it off, started it back up, light was still on but it ran fine. Light went off while driving to work today :dunno: I assume one or both sensors need to be replaced, but it doesn't make sense to me that sometimes they would work and sometimes it acts as if there's a complete failure? Worth noting, I replaced the intake book right after I bought it. Not sure about plugs but I'll check next time I'm under the hood.

This is interesting because now that I think about it, the codes seem to come up when it's really humid outside or when it rains. So there might just be a fuse I need to replace?

P.S. - I just re-read the first post and noticed that bit about the battery. I just replaced mine because there were a couple mornings where I had to jump start it, even though the battery was barely a year old. Could a battery really cause an issue like this?

The light came back on and it's running even worse, so I'm going to look at fixing it this week. I have the following codes:

P0161 - O2 Sensor Heater Circuit, Bank 2 Sensor 2
P0135 - O2 Sensor Heater Circuit, Bank 1 Sensor 1
P1345 - Misfire with Fuel Cutoff, Cylinder 2

The one about "no output from O2 sensor" is gone. Can anyone link me to a good resource for troubleshooting O2 sensors? I've seen some resources but nothing specific to the X5 / M54.

Also, since the codes describe a fault in the heater circuit and not the sensor itself, can I assume that buying new sensors won't necessarily be the fix? Or is the "heater circuit" all built into the sensor? Could it be something else that's the problem? Clogged cat, faulty DME?

Heater circuit is built into the 02 sensor, so buying a new 02 sensor will get you a new heater circuit.

As upallnight said, there were plenty of threads on these codes... before venturing into the oxy sensors, you need to find oout why you are getting misfires - this applies to both fellows with the problem... the DME will shut off the fuel to the problem cylinder to avoid FURTHER damage to the o2 sensors but, first, the damage may have already happened, and second, if you do not rectify the problem up the stream, your new sensors may get damaged too... and the cats don't like fuel coming down either, and the misfires can cause that happen...

check the reason for misfires... switch the coils on the question cylinder, see if the problem follows... pull spark plug (if plug is old or questionable, consider replacing all, as a maintenance item), switch to another location...

obviously, check for vac leaks, start with air filter, move to MAF, check the boot, check the throttle flap, clean if needed... check for vac leaks around the engine...

while a battery may cause a multitude of totally unexpected behavior, chances are it is not reason for misfire - unless we also alternator issues, that spikes voltage...

in other words, what i am trying to say, do some basic troubleshooting before starting throwing parts at the problem...

All the above. I would place a bet, that the DISA valve is also bad and sucking air. My kids drove the snot out of my 2003 x5 3.0 5-sp. since 2008. I finally made it my daily driver. Multiple codes.............. Positive smoke test. bad idle O2 codes, etc.
Replaced plugs, started using non ethanol fuel, repaired the DISA valve, replaced the Post cats. O2 sensors. and Voila. all codes were gone. She runs like a top. My 2 cents.

I had similar problems with my 01' X5 3.0 auto when it had 162K miles on it. It turned out to need a new Disa valve, plugs and all O2 sensors replaced. Checked all the coils with OHM and they were perfect. It now has 178K and returns perfectly smooth acceleration and amazing 21-22mpg highway. This site was amazingly helpful in diagnosing and fixing the problems. I also had assist with a local shop in Springfield,OR. BTW, I drove the car cross country last winter after the repairs.
Minus new BM trouble U issues the engine systems are flawless.

Thanks! So, on my list of things to look at, in order:

Air filter
MAF
Spark plugs
Coil packs
DISA valve
O2 sensors
Fuel filter

Intake boot was just replaced, and I was told that the dealer I bought it from did the spark plugs, but who knows.

Not hearing any noises from the DISA valve, and up until this weekend it always idled and ran smoothly as expected...BUT I have noticed that recently, when taking off from a start, occasionally it hesitates, then goes to feeling like I just floored it. So I will definitely check it.

I would check for vacuum leaks at the disa onring. 5 dollar fix. Then look at spark plugs if they haven't changed.

If that's it, is it possible to buy replacement seals from the dealer? Or should I get a kit like this one? Tried to find the parts on realoem.com but all I could find was the entire assembly.

RealOEM.com * BMW E53 X5 3.0i Intake manifold system

If that's it, is it possible to buy replacement seals from the dealer? Or should I get a kit like this one? Tried to find the parts on realoem.com but all I could find was the entire assembly.

RealOEM.com * BMW E53 X5 3.0i Intake manifold system

How many miles on your DISA? if over 100k I would just get the repair kit, its wonderfully engineered.

I have 70k on my car so my DISA is in great shape, I only needed to buy the O-ring seal for it (G.A.S. sells the O-rings separately on the website!), and I figure when it gets up in mileage and with some more wear down the line, I will install the rest of the kit and probably another new seal when the time comes.

You'll be able to tell if you have a leak at the seal, bc when you unbolt the DISA if you can pull it out of the manifold rather easily, its bc of the seal. You'll also notice it will probably be flat as all hell too, which I noticed. Kind of a pain to scrape the old one out but gave me some time to clean the DISA too. $5 fix. If you need to do the whole repair kit bc of age/mileage, its simple to do and costs 80. I'm thinking about getting the reduced pressure coolant cap from him as well.

No idea how many miles are on it. My X has around 152K so presumably it's been replaced or repaired at some point. Suppose I'll decide what to do when I take it off. So where can I get that seal if that's all it is? Would NAPA have it maybe?

Presuming thinking its been replaced isn't really doing much, not to be a dick. It takes 30 seconds to take the DISA off the car and test the condition of it, by checking the vacuum pot and seeing if the retaining pin is starting to loosen up (you DO NOT want that in your engine)

At your engine's age and mileage and given that you didn't buy it from an enthusiast, I would almost bet that the DISA is original, and at the very least the o-ring is toast on it and you need a new one. If it were me, I'd just pony up the $80 and do the whole repair, as I've heard some horrible stories of DISA's that have aged, subsequently fallen apart in the manifold and screwing up some major shit. Wouldn't you rather take it off the car real quick to see if its in good working order, before shrugging off the repair kit?

However, if you must do just the seal, its $5.65 shipped for O-ring from GAS, I presume you can wait a couple days for it to arrive in the mail?
Product M52-tu & M54 O-rings

Oh I do plan on taking it off, I actually edited my post to make that clear just as you posted that last reply :) Will post back with results.

Good deal man :)

Let us know how it looks! and read GAS instructions on their website, they make it very clear also how to test DISA function and visibly how a healthy DISA should look!

DISA valve looks OK. The seal could stand to be replaced, but it's not completely flat. And the air filter and spark plugs are somewhat worn (I'll replace them) but they're not abysmal. I'm thinking there must be a vacuum leak as the misfire is not contained to one or two cylinders. It's random...every time I pull the codes, it comes back with different cylinders. And now the O2 sensor codes are gone. Next thing I plan to check is the PCV system.

What I don't understand is, why does it only run rough when the SES light is on? Once I clear the codes or sometimes if the light goes off on its own, it's fine.

good to hear you only need the 5 dollar seal, and at your mileage I would definitely say the plugs could use replacing (NGK set is 40 bucks)

My car was noticeably smoother at 68k miles when I replaced the plugs. And obviously if the air filter is dirty it will help too. Did you find excessive oil on any of them?


You may want to try the old mechanics trick and spray WD-40 over vacuum hoses in the engine while the car is running, if you hear the idle dip or rise, you found your vacuum leak :)

the engine's running characterics change with the SES light because the computer shuts down the info flow from some of the sensors and runs the engine on predetermined, fixed values that do not reflect the actual state of the situation...

there are many codes generated during the engine (and the whole car) operation, most of those codes do not trigger the SES light, they are just stored in the memory... at some point, they may reach a threshold that trips the light but if the condition does not manifest itself again, the light resets, while the codes are still stored in the system. if the code (problem) severe enough, the first code can turn the SES light on, and some SES codes do not reset once the issue is gone, you need to clear them from the memory.

most OBD readers will read basic, industry standard codes, and those codes are present in the OBD II socket... however, since the BMW went away from a dedicated round shaped data port and integrated the info flow into the OBD port, that port also has a wealth of BMW specific information that can be pulled by a BMW specific software and being manufacturer specific protocol and info flow, they packed a lot of info into that data port...

you should try to get yourself diagnostic software and a cable (many folks here used the romanian dude on ebay for the package deal) and see if you can monitor your car, both live and just reading the modules...
or, find a friend who has the package already on their laptop... but remember, this is just another tool in your toolbox, it does not replace all the other recommendations you heard here before...

Vacuum leaks
 

Side Note. Spraying wd-40 to look for vacuum leaks is crude and will only work if the leaks are generous. Seafoam, brakecleaner, carb clean, anything works, just not as elegant as a smoke test.

The best way of checking for vacuum leaks is to perform a smoke test. If you are a gearhead and have other projects, it is worth $50 or $60 to purchase a smoke making device. I use one designed for the DJ (think fog filled room and disco). It is cheap and easy to use. Just hook up to any vacuum line and turn the machine on.

You will be able to see if there are vacuum leaks any where, not just where you squirt the wd-40 or whatever you use.

It runs rough with the SES light on because for some DTCs the computer will shut down the injector(s) in order to prevent damage to the CAT. With the injector(s) shut down now you have one less cylinder firing.

You may have a slight miss (which you may not be able to detect) which allows the cylinder to fire but the computer will know that the cylinder is missing.

I have not seen a post where the MAF sensor has been cleaned or tested. Since MAF contributes to fuel mixture it can be the cause of lean codes and or pre cat O2 sensor faults.

I suggest cleaning the MAF thoroughly with MAF cleaner, easy to do and doesn't cost much. If you do so, be sure to spray all wires, liberally several times-- after you give the wires a good spraying you can tell where they are back to like new and where you haven't sprayed enough.

True, I haven't tried cleaning the MAF, I didn't have the proper cleaner when I was checking things last night. Can anyone post procedure for testing the MAF? I have a multimeter and have done it on other cars, but for the X5 I can't seem to find what needs to be probed and what the readings should be.

One test is to remove the connector from the harness. If MAF is working properly the idle should increase.

The following should help: How To Test A Bosch MAF Sensor - YouTube

If you are not familiar with how to clean the MAF this will help: How To Clean a Mass Air Flow Sensor (MAF) - YouTube Even if do know how to clean it the on screen dialogue is fun to read.

I don't really get what the guy is doing with the nails in the video of testing the MAF sensor. What are they connected to? Isn't that dangerous anyway? Also, does anyone have a link to procedures for testing coil packs?

Small update...I can now feel it misfiring even when the light isn't on. Installed a new air filter, cleaned the MAF, and made sure all the hose clamps on the intake tract are tight. It ran a bit smoother, but not normal. Changed the plugs, and that made no difference. But after looking at them in better light, I can see that 3 of them look worse than the other 3. It's a little hard to tell in this picture...but these are the plugs pulled out in order from the back of the engine to the front.

https://lh6.googleusercontent.com/-P...124_160853.jpg

The 2nd, 5th and 6th plugs are darker / look more fouled. That seems pretty random.

Now, I had my generic scanner hooked up to it, and after a while of idling at cold start it's throwing P0174, system too lean (bank 2). No other codes yet and the light isn't on. But I'm afraid to drive it like this, as I imagine it could cause some damage?

So...next steps? Thinking I will replace the fuel filter first, as that probably needs to be done anyway. Then I suppose I have to pull the intake and check the CCV system. What about the valve cover gasket, could that cause this?

Before pulling the intake manifold, see if you have a vacuum leak. P0174 is a lean condition code which can results in a misfire. A lean condition code is mostly associated with a vacuum leak.

I would look at the plugs that are not foul as that is what a lean condition can do to them.

I've looked for leaks as best as I can without having a smoke machine...DrRick, which machine did you get that was only ~$60? The ones I've seen are more expensive.

As for the plugs, why would it be lean only on those three cylinders, especially since they're in different banks?

Driving your X with the symptoms you have shouldn't cause any harm. That said, I would get to a good Indy shop and get the smoke test soon. The smoke test you want to get is a pressurized smoke test that is done when the engine is not running.

As mentioned, vacuum leaks are a common cause of misfires. They are also a common problem as vehicles age.

The video shows nails used to make contact to the voltage output. It is not dangerous. Many amp meters have alligator clip connections that would be attached to the nails.

Misfires due to problems like vacuum leaks are often random cylinders.

so i have replaced my two front o2 sensors and cleaned MAF. I am still getting the P0141 sensor 1 bank 2 error now

all other codes seem to have gone away running too lean , misfires etc... so far so good knock on wood

I guess i should check the disa valve next or move on to rear sensors?

car has 124k on it and plugs were done at 98k and i replaced valve cover gasket at 110k
:dunno::dunno:

Rear sensors are part of emission system.

Have you eliminated the potential of a vacuum leak?

If it helps, my issue turned out to be that one of the hoses going into the PCV valve had come loose. So check the DISA for sure, but if it looks OK, I would start checking for vacuum leaks under the intake.

i have glanced over real quick for vaccum leaks i seem to get the code if i park the car for at least 30 minutes then take off again and i usually get it withing 5-10 min

have not checked disa yet

Sorry to bump this thread again, but the SES light is back on. Codes this time:

P0455 - Evaporative Emission Control System Leak Detected Gross Leak
P0135 - O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1
P0161 - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 2

So the O2 sensor codes are the same as before. No misfire codes or codes about running lean this time, though. No change in power or gas mileage either (still averaging around 20). I cleared the codes and the O2 sensor codes came back within 50 miles, but not the EEC leak code. The car drives fine and has been without SES for months.

This time around I'm noticing a couple things that are indicative of the DISA valve---whistling noise part throttle, and occasional unexpected acceleration as if a turbo just kicked in---so I plan to go ahead and rebuild it before anything else. Before I spend money on the O2 sensors as well, is there anything else I should check, specific to the heater circuits? Maybe a fuse or relay has gone bad? Or maybe a connector is loose somewhere?

O2 sensors may be fine. If there is a problem upstream the O2 codes may be only a symptom of the core problem. I would have a smoke test done to check for vacuum leaks. If not a smoke test I would let the engine idle and spray starting fluid where a vacuum leak could be and see if engine increase rpms indicating a vacuum leak. First place I would check is the plastic air intake tube. If vacuum leak is there you should be able to see it.

I would expect the DISA valve to be rattling if it is bad but assuming it is the DISA valve you should fix it right away as it can cause serious engine damage.

Well it has been a while since I looked, but...smoke test was done back in February and it was found that some of the PCV hoses were bad. Replaced those. Air intake tube was replaced when I bought the car a year ago, but it could be that it's come loose (or even cracked again as I live in a very dry climate).

Last time I pulled the DISA valve, it wasn't the valve / flapper itself that was bad, just the seal. The seal wasn't bad enough to replace it right then, but I think it is now, just based on symptoms. It'd be preventative maintenance more than anything. Will check it again soon.