ODB read error
 

Appreciate any constructive input on this.

Question 1:
Has anyone ever had trouble pulling ODB II codes on a 2002? I have a reader that I know to be working but only am able to pull 'error' from my X5.

Question 2:
Attempting to pull code because idle is rough to the point of stalling, believe one of my ignition coils has gone bad. SES light is on. As long as fuel is being fed to the engine (accelerating) I wouldn't even know I have a problem, short of the smell of unburnt fuel. If I take my foot off of the gas pedal while at speed it immediately goes into rough idle. Presuming this to be enough information could someone confirm ignition coil as probable problem?

Thanks for any help.

1. Have to ask, engine wasn't running when trying to get the codes right? I have 2004, but never had a problem getting codes.

2. I had a similar problem, diagnosis was -> misfires on some plugs, I changed all the plugs and swapped some coils to see if I could find a bad coil. Misfires still occured. I then changed my brand of Gas and I used Techron Fuel Injector cleaner. My misfires went away but I still occassionally have a rough idle.

If a cylinder isn't firing it would be cooler to the touch (don't try this on a really hot engine, maybe use gloves, a thermometer or an Ice cube to find a cold exhaust).

Appreciate the quick reply
 

Thanks for the quick reply.

I did try with auto off and key in position 2 (just prior to engaging starter). Fuse looks fine and guess I am going to visit an autozone and see if their scanner can somehow pull what mine cannot?

Thanks for the input on the misfires, that will go a long way to helping me diagnose if I continue to strike out on pulling that code.

I had been thinking bad gas too, but the problem occured at about 1/4 tank and the other 3/4 burned fine. Then I filled up thinking I would dilute any remaining bad fuel but problem continues...

Thanks again for the help.

My Peake always works with our '01 as does the Scanguage II. You may have lifted junk from the bottom of the tanks. Could need a fuel filter change as it also houses the fuel regulator.

Thanks Zulu95 and cam for the help.

I was able to pull the codes yesterday and realized that I was being an idiot and not seating the ODB scanner properly originally. With it properly seated and after resetting codes and then driving to be sure they are all valid this is what I have got. Any additional input much appreciated.

Just to reiterate symptom. Rough idle to the point of stalling, drives perfect when accelerating. Not a problem if no one else were on the road. :) When not feeding fuel to the engine goes back to rough idle/stall even at highway speed. I originally thought ignition coil and misfire but obviously must be off.

Codes:
P0103 Mass or volume air flow circuit high input
P0172 Sys too rich (Bank 1)
P0175 Sys too rich (Bank 2)
P1085 Fuel Control limits too rich (Bank 1 Sys 1)
P1086 Fuel Control limits too rich (Bank 2 Sys 2)
P1500 Idle Speed control valve stuck open *not shown since reset of codes
P1603 Control Module self-test torque monitoring

Thanks for any help or ideas.

Clean your mass airflow meter with wd40 , clean the wires on it, connector and all.
You should also clean out your idle control valve, it being stuck in any one position is a sign of carbon buildup. Ultimately you need to check your mass airflow meter and make sure all your hoses are attached correctly. You might end up needing to change your idle control valve and mass airflow meter. Gluck and lemme know.
P.S.
you can check your coils by unplugging and plugging the wire that goes to each of them. If the coil is working, when you unplug it your engine idle will change instantly. If/when you come to a bad coil, your engine idle will not change. (because it was not working).

looks like faults stored for a 3.0l if the intake boot is not torn, you may need an engine wiring harness

Thanks for the help BMWFiend. Did the moonlight mechanic thing last night and got at the MAF, Throttle body and idle control valve. The MAF and throttle body looked what could only be described as immaculate. Its possible that these had been replaced prior to my purchase of vehicle at 65k miles.

Idle Control valve did have some (very dry) carbon dust on the 'guilletine' viewable on the side of the ICV, that looked half open. I was able to manipulate it with my finger. Don't know if that's normal but figured I would go ahead and replace for the 119.30 it costs and eliminate that as a possibility.

Will keep you posted and continue to appreciate input from anybody out there that wants to add their two cents.

Good that the rest of it was clean, but the mas air flow has electronic components to it, which would be responsible for it malfunctioning, did you double check all the hoses and make sure they're all attached correctly

Thanks for the quick reply and again for the help.

Did check the hoses, they were all still connected, tight and not dried out at all in general looked in really good shape. . I hear you on the MAF sensor and electronic components but honestly the thing looked new. If idle control valve doesn't set me straight I'll probably reassemble and then do the coil remove one at a time to eliminate that. Then go back finally to the $300 MAF. Also believe in the case of the MAF fail a direct ODB should point right to that as failing component.

Have to say that I'm not impressed with the ODB standard...pass me my walker and can of Moxie.

Anyway, thanks much for all of the help and will write back tomorrow after idle control valve put in.

ok

...still working. Part arrived yesterday, more this weekend. Thanks again for help.

Well new idle control valve in there and unfortunately no change in behavior. Did go along pulling coil connections to see if I could change behavior, but sound I'm getting is slightly different so I will have to assume no misfire. Plus no codes for that.

Went to the dealer to pick a tech's brain. After giving him symptoms and codes he put into his computer and pulls up a service bulletin for three batches of wiring harnesses. Sent me home with numbers check against my own the Engine wiring harness. Sure enough I have 12517513548, one of these sets on my harness. I remain skeptical that this harness is at fault, though I realize their data points in that direction.

I am a stumped now. Next step I guess is to bring it to my local indy, give him the history and get his take. Up until this point I am the only one that has actually heard and experienced the stalling/misfiring.

Wiring harness looks like a lot of labor and 500 beans for the parts.

Thanks for reading and don't be shy about additional input.

Looks to me like either the harness problem or mass air flow sensor problem. With problems like this the multiplicative vaules set in the DME are usually pegged at 12%, so I swap with a known good MAF and drive it a few miles... if the multiplicatives start coming back to normal range you know you had a bad MAF. If that don't do it.... harness time. (since you fall within the bulletin range, you likely need that damn harness)

And FWIW I would use some MAF cleaner from autozone instead of WD40 on that MAF sensor... the oil film will fudge the readings and make you run more rich vs the cleaner that will remove the film and leave it perfectly dry with no residue.

I looked to this old post and noticed that you had exactly the same problem then me sometimes ago, the engine ran very well from full tank to 1/4, then very roughly and even stalled below 1/4. I spent a bit of time to find the cause! In the case that this is a similar cause, there is a small o-ring on the fuel tank, LHS, just where the pump is located. This non-Viton o-ring tends to crack with age due to unleaded fuel, so the pump sucks air instead of fuel when the fuel level is too low. As the fuel tank is in 2 parts, the fuel cannot be pumped from the RHS to the LHS. Go to real OEM parts and you will see the o-ring. Hope that this is the same problem, cost is about 2 USD!...

This is my new mechanics number, call him, give him the symptoms and see what he says,Owners name is Bill name of the shop is L&M Foreign Cars (718)451-9894, I went there last week and he's pretty legit, 2nd generation technician, opened the shop in 69,

Drive the car until the service engine light comes back on, scan it and tell me what the code it, It could be the wiring harness, but more likely is the mass airflow

Thanks for all of the help and the follow up BMWFiend, you were right all along with the Mass airflow sensor and replaced it yesterday. Bavarian Chariot is back on the road and I learned quite a bit.

Good luck out there until next time and thanks again.

No problem, glad I could help.