I've had my 2002 s40 turbo for the past year and it has ran like a dream until recently. At first i had problems starting it up, in which i would need to give a bit of gas while cranking for it to turn over. In the past two weeks i've had multiple occasions where i had been idling at a light and the car shuts off.

I've gotten the following error codes: ECM-0C Boost Pressure Sensor, ECM-16 Front Heated Oxygen Sensor signal, ECM-14 Mass air flow sensor Faulty Signal, ECM 45 Misfire, emission level, faulty signal, ECM-25 Long-term Fuel Trim. Lean.

After speaking to some of my mechanic friends they believe all my problems stem from the o2 sensor and/or the MAF. I would appreciate any help or ideas from everyone here. Having the MAF, o2, and boost system all giving out error codes is freaking me out!

 

A bad front (top) O2 sensor won't cause hard starting or misfires or shutting off. Normally a bad top O2 causes poor gas mileage as the car runs too rich.

I'm just guessing but I'd bet on the MAF as the problem. It would definitely explain all the different symptoms. I'd try cleaning it with MAF cleaner and resetting the codes first before paying for another MAF.