OBD II Codes

You don't say the mileage, but it could be as simple as an oxygen sensor being out of range (P1188). P0170 is for fuel trim. this can also be caused by an failing O2 sensor, but also can be the result of either a vacuum leak or bad injector. It depends on if the system is measuring too much or not enough air in the mix. I'd rule out the air filter as that would effect both banks, not just bank 1.

Kyle.

The 528 only has Bank 1.

When I got that message on my 540i, it turned out to be the Mass Air Flow Sensor. It could, however, be quite a few other things causing the fuel mixture (trim) to be incorrect for a given set of circumstances.

Tim/

Uhhh... no.

Incorrect.

The E39/528 and all other M5x based engines have two banks. There is a split exhaust manifold on these engines. 1-3 in the front (bank-1) and

Been that way since OBDC-II was started in '96 on all 6 cylinder BMWs.

I wasn't aware of that. I get what they did, I just didn't know they did it.