[Orion4]

2013 335i Sportline Sedan (stock) with 104,833 miles. I have a reoccurring, random amber engine alert. It comes and goes with no apparent pattern or cause. No change or degradation in drive-ability, performance or gas mileage Been dealing with this for a couple of months. When I run the BT Diagnostic software, all I ever get is below.

Current Fault Codes:
-118001: Mixture control: mixture too lean
-101F01: Throttle valve opeing angle, absolute pressure, intake pipe, comparison Pressure too high

Does anyone of any thoughts on the cause(s)? The randomness is making it difficult to diagnosis. Thanks for any insight.

[Korvo]

Originally Posted by Orion4

2013 335i Sportline Sedan (stock) with 104,833 miles. I have a reoccurring, random amber engine alert. It comes and goes with no apparent pattern or cause. No change or degradation in drive-ability, performance or gas mileage Been dealing with this for a couple of months. When I run the BT Diagnostic software, all I ever get is below.

Current Fault Codes:
-118001: Mixture control: mixture too lean
-101F01: Throttle valve opeing angle, absolute pressure, intake pipe, comparison Pressure too high

Does anyone of any thoughts on the cause(s)? The randomness is making it difficult to diagnosis. Thanks for any insight.

Are you running any sort of a tuner?

[Orion4]

Originally Posted by pdegene

Are you running any sort of a tuner?

As stated "stock"

[cfm56d7b]

I will go through my archives to look for all N55 codes. This problem has been reported in the past.

Is your charge pipe still OEM it was it replaced at some point?

[cfm56d7b]

I just reviewed N55 fault codes. According to BMW, these are the possible issues:

- Oxygen sensor before catalytic converter defective
- Mass-airflow sensor defective;
- Defective injectors; seen this before myself ...
- Intake-manifold pressure sensor defective
- Intake-air temperature sensor defective
- Camshaft position sensor defective
- Defect in high-pressure fuel system; seen this before ..
- Defect in low-pressure fuel system; seen this before ...
- Intake system leaking
- Oil cap not sealing; also have seen this before ...
- Leak in exhaust system

Hope this helps. I'd start with the more obvious and less expensive items like mass air flow sensor, oil cap, and other sensors like intake manifold pressure sensor.

[Orion4]

Still running the original Charge pipe (I know! Living on borrowed time!)


Thanks for the info. I'll work through the list pretty much as you recommend. My initial thoughts were a failing/bad O2 sensor. I would think if some of the items were the culprit, i would be experiencing some degree of performance and/mpg degradation, which I am not.

Thanks again!

[zinner]

my guess is a vacuum/intake leak before the throttle body.

[Orion4]

Well, went through most of the list of suspected culprits yesterday the best I could without tearing much a part. Couldn't detect any vacuum leak or cracks in the OEM Charge pipe. Pulled the MAF and Boost sensors, cleaning both with CRC MAF cleaner and reinstalled.



Started engine, drove around the block. Ran the BT diagnostics which showed no fault codes. I had cleared the old ones before I started chasing ghosts. Drove about 70 miles yesterday in all ranges of speeds and accelerations without any alerts. Thought it might be solved. HA!!



This morning at start- Amber Eng Light back. Ran diagnostics receiving only the "118001- Mixture control: mixture too lean" fault code. Cleared it and will see how quickly it comes back this time.



The car continues to perform normally in power, drive-ability and mpg.



Is a possible developing crack in the CP or failing MAF possible culprits?

[lucasmiller2015]

Originally Posted by Orion4

Well, went through most of the list of suspected culprits yesterday the best I could without tearing much a part. Couldn't detect any vacuum leak or cracks in the OEM Charge pipe. Pulled the MAF and Boost sensors, cleaning both with CRC MAF cleaner and reinstalled.



Started engine, drove around the block. Ran the BT diagnostics which showed no fault codes. I had cleared the old ones before I started chasing ghosts. Drove about 70 miles yesterday in all ranges of speeds and accelerations without any alerts. Thought it might be solved. HA!!



This morning at start- Amber Eng Light back. Ran diagnostics receiving only the "118001- Mixture control: mixture too lean" fault code. Cleared it and will see how quickly it comes back this time.



The car continues to perform normally in power, drive-ability and mpg.



Is a possible developing crack in the CP or failing MAF possible culprits?

Do you have / can you get ISTA/D (dealer diagnostic software) installed on a laptop? If you run the vehicle test in ISTA immediately after you get the warning, it will give you a "test plan" that tells you exactly what to check based on the codes, sensor data, etc.

If you don't have it, all you need is Windows laptop or VM, a K+DCAN cable, and the software (at bimmergeeks.net/downloads)

[Orion4]

No, I don't. Looks like I'll need to install it. Guess it will finally force me to up grade the WIN VM package on my Mac Book Pro to WIN 10.