If anyone can help I would appreciate it. I have a 2002 Volvo S40 with 111,978 miles on it. I recently replaced my MAF sensor and started to get engine codes PO101,PO102, and PO172. The car idles rough and will stall after some time of idling. Air filter is brand new, and the throttle body is clean. Clearing the codes with a scanner doesn't help, the codes come back immediately. Anyone have a suggestions to diagnose the problem?

 

Put the old air mass meter back in, clear the codes and see what returns?

 

Thank you for the reply. I put the old MAF in still throwing codes.

 

I'm betting there's an air leak in/around the MAF - double-check your work.

 

I would check your PCV health while it idles too. With the engine idling, remove the oil fill cap and seal your hand over it. Positive pressure = Bad, Vacuum = Good. And like Habby said, check for an air leak.

What made you replace your MAF sensor in the first place?