Hey guys, my car has been running well but if I take it on the highway for about an hour and I pull off the idle is really rough and irregular and seems like it wants to stall. I also received the following error codes through my insurance tracker:

P0301, P0302, P0304 (Cylinder misfire codes)
P0101 (Mass Airflow Sensor range eroor)
P0172 (System too rich)

I checked my mass air flow sensor and it appears to be clean, and the air filter is pretty new. I turned the car to on (but not ignition) and I checked the 3 cables going into the MAF sensor and none of them are supplying the voltage needed to power the sensor (the red one however is supplying .05 volts... Not sure if that is normal or not). Anyway, I really want to fix this and I can't figure it out, I can't find any blown fuses so I am puzzled. Also, if I don't have the capability to get the input wire to work, could I technically run one from the battery terminal directly into the power input of the sensor? And if I did that how would I do it and what fuse should I use?

Also IDK if it is relevant but the AC doesn't seem to be blowing cold air, it just blows hot engine air!

Thanks!

 

what year is the car? you can try digging through the wiring diagrams to see if you can find a junction/connector or trace back to a specific fuse or relay (volvowiringdiagrams.com). On your AC, does the compressor kick on at all? Can you force it to kick on by jumpering the low pressure sensor (up by the firewall on the metallic line)? depending on the model/year, MAF sensor codes are often caused the throttle body (or ETMs on the 5 cyl models) vs the MAF sensor. Did you try measuring the voltage on the connector (not the MAF) with somebody cranking the engine as well as position 2?

 

I recently replaced my MAF on a 2000 v40, after eliminating all other codes. Engine Light was off for a while, now back on with P0101. If it isn't the MAF sensor, I am thinking wires. Were you able to trace your problem and repair? I would be interested where I should start on mine. Thanks

 

the P0101 can be set off by vacuum leaks, dirty throttle body etc. There's not a lot to trace for the wiring - You can go to volvowiringdiagrams.com to see the pin number on the ECU but I'd probably check the vacuum lines - possibly with a smoke test to rule those out, check the intake boots/tubing for leaks, clean the throttle body and idle air valve. Last considerating is the MAF. If you used an after market brand, you may want to go to a recycle yard and pick up a used OEM MAF to see if that behaves differently. I've read other posts where replacement parts didn't quite come up to spec.