Expert: Don Berlan - 1/31/2009

Question
QUESTION: my check engine light is on and i"m trying to get my 98 bmw 528i smoged. everytime i get the computer scanned it reads that its maf sensor. i've changed it with others that were good and yet the check engine light still comes on after 10-15 miles after i erase th comp. what's wrong ith my car? please help!!! i just need my car to pass smog.

ANSWER: Although it may set a code for the mass air flow,it doesn't mean to replace the sensor.There maybe(as you found out)something else setting the code.You need to recheck the code and what else may cause it to set.Not knowing the code I can't really give you a positive direction to go.Making sure all your rubber hoses and clamps are tight,also any oil leaks as they too will cause an unmeasured air leak.

---------- FOLLOW-UP ----------

QUESTION: two codes popped up: 1189 and 0173. as a follow up can u give me a better idea of whats wrong?

Answer
Well both codes deal with fuel control bank 2 sensor 1(1189) and fuel trim bank 2(0173).Both being on the same side of fuel control being bank 2.You need to watch the operation of the oxygen sensors.Sounds like the front sensors are failing.Check them probably the sensors are weak and need replacement.