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-   -   Service Engine Light - Code P1175 (http://www.bimmerfest.com/forums/showthread.php?t=670483)

necero 01-16-2013 12:09 PM

Service Engine Light - Code P1175
 
Hi Guys

Trying to get ideas of what might be wrong with my car. 2000 540i/6 with ~126k miles. Short story is my check engine light came on. Took it to the local auto place and the code came up as P1175 (fuel trim adaptation additive bank 2 malfunction. Explanation: large vacuum leak on engine).

What's happening is for the first few minutes after a cold start my idle is pretty rough. Every once in a while when the car is moving and I take out out of gear and don't have the clutch pressed the revs will drop to 0 and the engine will die. The problems go away as soon as the temperature gets to the normal running temp.

I have searched around and everything I have found shows that P1175 is accompanied by P1174. I have yet to find anything that shows only P1175 being thrown, which is my case. From reading around it seems it could be anything from the MAF sensor to gaskets/o2 sensors.

I recently replaced the alternator (for the second time, first replacement alternator went bad) a week ago or so and am wondering if the vacuum leak could have been caused by anything I may have taken off and not put back properly (specifically the air filter housing). My dad also decided he wanted to clean my MAF sensor just before I did the alternator. I am curious as to if there is the possibility of that being cleaned or re-installed improperly which could be causing the problem.

tl;dr - CEL throwing code P1175 only. Any help or ideas would be greatly appreciated. Thanks!

edjack 01-16-2013 12:43 PM

How many miles on the pre-cat O2 sensors? If original, you're overdue for replacements.

You could also take it to a shop for a smoke test.

necero 01-16-2013 12:46 PM

Quote:

Originally Posted by edjack (Post 7318225)
How many miles on the pre-cat O2 sensors? If original, you're overdue for replacements.

You could also take it to a shop for a smoke test.

I assume they are the originals, but am not positive. I have all of the service history so I could go digging and find out.

DHoang 01-16-2013 06:08 PM

That p code by itself is pointing to your air mass sensor, likely contaminated. You are dead on in suspecting that your dad may have done more damage than good.:rofl:

necero 01-17-2013 07:52 AM

Quote:

Originally Posted by DHoang (Post 7318899)
That p code by itself is pointing to your air mass sensor, likely contaminated. You are dead on in suspecting that your dad may have done more damage than good.:rofl:

Yeah, I'm hoping it's just that. Do you think just cleaning it would solve the problem or is a new one in order? Is there any way to test and see if that's the issue? I think I remember reading in other places that people unplugged the MAF sensor temporarily and the rough idle stopped which meant it was an issue there.

Either way I think I'm going to replace my pre cat O2 sensors, seems like something that needs to be done eventually anyway.

bluebee 01-17-2013 08:01 AM

Quote:

Originally Posted by necero (Post 7319939)
Yeah, I'm hoping it's just that. Do you think just cleaning it would solve the problem or is a new one in order?

I typed /MAF F3 in the bestlinks, and these came up which may help:
- Mass air flow sensor (MAF) & idle control valve (ICV) require periodic cleaning (1) (2) & buying a replacement MAF cheaper than the BMW MAF (RangeRover MAF) (VW MAF) (Hyundai MAF) & cleaning the throttle body (1)

necero 01-17-2013 08:06 AM

Quote:

Originally Posted by bluebee (Post 7319966)
I typed /MAF F3 in the bestlinks, and these came up which may help:
- Mass air flow sensor (MAF) & idle control valve (ICV) require periodic cleaning (1) (2) & buying a replacement MAF cheaper than the BMW MAF (RangeRover MAF) (VW MAF) (Hyundai MAF) & cleaning the throttle body (1)

Awesome, thanks a lot. I was just looking for throttle body/idle control valve cleaning instructions.

Edit: Am I correct in reading that the 99 and up model years don't have an ICV because of electronic throttle linkage?

edjack 01-17-2013 03:25 PM

Correct for the V8.

necero 01-18-2013 07:54 AM

Quote:

Originally Posted by edjack (Post 7320837)
Correct for the V8.

Thanks, just wanted to make sure. Just an update. At work I cleaned the MAF again and let it sit for a few hours before going home. When I started the car to head home the SES light was off. During my drive home, after about 5 miles or so, the light came back on. Would I be right in thinking that means it's a faulty MAF sensor causing my issues? I'm going to change out my pre-cat O2 sensors as well since they need doing, I just hate not knowing what exactly is causing the problem.

Thanks for everyone's help thus far.


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