So I've been dealing with the P1188 and P1189 codes for about 3 years now and have not been able to pass an emissions test. The most recent tag on my license plate is from 2006!

Anyhow, long story short:

1. Indy BMW mech 1 could not fix it after $2500 worth of parts and labor.
2. Crevier BMW service department could not find the problem after having my car for more than 3 weeks and $1100 (included changing accessory belts and water pump, reflashing DME, new intake boot and CCV).
3. Certified Smog repair shop could not find the problem after $600 in repairs.
4. Indy BMW mech 2 quoted $3000 with a laundry list of parts that included a new DME, engine wiring harness, new MAF, and some other stuff.

After spending over $4200 I was not anxious to spend another $3000 with the 2nd indy mech so now I've decided to dive into this thing and fix it myself.

I bought an OBDII scanner and have been searching the forums for info on these codes. The Actron scanner that I have has the ability to look at the freeze data that is stored when the error code is set off. The info below shows the data:

RPM: 1675
Load Value: 69.4%
Coolant Temp: 194*F
Short Term Fuel Trim 1: -20.2%
Long Term Fuel Trim 1: -8.0%
Short Term Fuel Trim 2: -11.8%
Long Term Fuel Trim 2: -6.3%
Short Term Fuel Trim 3: -100.6%
Long Term Fuel Trim 3: -100.6%
Short Term Fuel Trim 4: -100.6.%
Long Term Fuel Trim 4: -100.6%
Vehicle Speed: 16 MPH
Fuel System 1: Closed
Fuel System 2: Closed

A note about the STFT/LTFT values for 3 and 4: I think the reason they are so high is because I had a leaky injector (stuck open) and the system was trying to compensate for the extremely rich condition.

My interpretation of the data is that I'm running rich and the DME is trying to compensate, am I reading it right? I believe that the CEL and DTC were set off by the STFT1 exceding -20%, can anyone confirm that? If I am correct then I believe that I can rule out an intake leak which would cause a lean condition.

What I'm planning to do is clean or replace the MAF. Hopefully a good cleaning will clear up the codes. Since the problem is with Bank 1 and Bank 2, I am assuming that the problem is with something in common with both banks, i.e. the MAF.

I will most likely have to change out the pre-cat O2 sensors since I don't know how old they are, but the MAF cleaning is first on the list. I'm trying not to spend too much more money on this than I have to. I'm also going to look into the injectors, FPR, fuel filter and pump to try to get to the bottom of why I'm running rich.

Also, can anyone tell me why there are 4 sets of STFT/LTFT values? Do they have to do with fuel trim at idle vs. under load vs. WOT?

Any help would be much appreciated!!!!!!!!Anaheim Hills, CA
'99 528i Sport, Black/black