Questions and Answers

Jetta Code P1128 Q. Dear Vince, I have a question concerning my 1999 VW Jetta. The check engine light keeps coming on. Right now it is on in the car obviously stating that something is wrong. I have a friend who has one of those computer machines that reads the codes and the code we got was P1128.

With further research P1128 in a VW/Audi means 'Long Term Fuel Trim - System Too Lean Bank 1. What exactly does this mean? Can you explain to me what I am suppose to do in a situation like this. I still drive the car hoping I am not ruining something. I took the car to VW and their response to this is I need to change the Mass Air Flow Meter.

My local mechanic whom I trust very much said he didn't get that reading. At this point I am very confused. Any information would be greatly appreciated.

Thanks,
Nandita

A. The MAF sensor could be bad. But the P1128 is triggered when the fuel mixture is so lean the O2 sensors are constantly in the rich position. I would look at the O2 sensors first. Then check the fuel injectors, fuel pump pressure and volume. Replacing the fuel filter is a good idea also. Vacuum leaks could cause the lean condition as well. I would make sure there are no vacuum leaks and that the oil cap and dipstick are firmly seated.

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