My wife has a 1998 S70 GLT Turbo. Sometime back the car was having issues with the engine stumbling while driving, both at constant speeds and under acceleration. The check engine light came on and the error code that came up was P103, Mass Air Flow sensor. I cleared the code but this started to happen over and over. Whenever this happened the car could be hard to start, could run erratically, and tended to stumble or stall when driving at steady speed or under acceleration. If I disconnected the lead to the sensor the check engine light would stay on but the car would run just fine.

I read that this could be a dirty sensor, a bad ground to the sensor, or a bad sensor. I removed the sensor and cleaned it carefully with alcohol. I reinstalled it and with the car running tugged on the wiring harness at every spot I could. I couldn't get the error code to trip so I figured the ground is ok. The error code continued to trip while driving.

I replaced the sensor with a remanufactured unit from Napa Auto Parts, it was less than half the cost of the new unit from Volvo. It was fine for a while, then started to stumble, stall, and throw a P103 error code again. Now it's doing it nearly every time we drive the car. I did this months ago so the 90 day warranty on the sensor is well passed.

So I figure either the sensor is bad and I need to buy a brand new one from Volvo or I need to take it in to my mechanic. My mechanic is honmest and talented but not cheap so both of these are fairly expensive options.

Is there anything else that might be causing this? A loose hose or wire somewhere? Is there any way to tell for sure that it IS the MAF sensor? Anything else I should check?

Thanks,
Scott

 

I've learned that you really shouldn't buy parts for Volvos from Auto Zone, Napa, that sort of place. I'd either get an MAF from Volvo or an aftermarket site like ipd. There's a small wire that connects to the underside of the MAF, I'd check that too.

 

Napa used to be so much better for parts 20 years ago when I was a kid. Makes me a little sad but thanks for the tip.

I was a little suspicious since this is a refurb part and it seemed to work for a while, but still reluctant to drop $400 on a brand new genuine Volvo part. Guess I feel more confident that the Volvo part may be the answer. Lesson learned, Volvos don't like cheap parts. I miss my old VW bug, so cheap and easy to fix.

Thanks,
Scott

 

Got the Volvo MAF sensor and installed it, car is now running just fine.

Scott