2005 S80 2.5T FWD, rough idle & stall

drjackmd · Post by **drjackmd** » 20 Apr 2016, 19:48

Hey! My s80 2.5T has just over 213k on the ticker. Ran well until today. Came back to my car after a couple hours at the gym. Was circa 80 degrees outside and sunny. Car turned over, sputtered, and stalled immediately. I restarted and it continued to sputter with eradic idle, but didn't stall. I reved the engine and the idle speed became steady. I pulled out of parking spot and began to drive away. I could feel a bit of hesitation in the acceleration, though it was very faint. With the windows down I heard a whistle as I accelerated. Six minutes later I was home. I parked in the shade for about an hour. Came back with my MaxiDiag Elite and started right up as if all was well. Three codes read:
930d ECU, communication error; signal missing
120d air mass; signal too low
121b mass air flow sensor; flow too low

I turned off the car and checked the MAF connection since I just changed the air filter the other day. Though maybe it wasn’t seated in the socket. I restarted the car without problem. I proceeded to erase to codes. As the codes were erasing the car sputtered but returned to normal idle upon completion. I let it idle for about 5 minutes. Rechecked for codes but nothing came up.

Could these codes be caused by vacuum leak? Is that whistling sound a vacuum leak? Where do I look for leaks and how to go about doing so?

...or do I look elsewhere for the culprit?

jbkeene · Post by **jbkeene** » 21 Apr 2016, 08:18

did you clean the MAF sensor?
maybe some dirt migrated while you were working in the area?
is air filter and housing seated properly?
I know...all silly things, but can certainly be overlooked sometimes

seems odd it would act up only after changing the air filter
yes, whistling could certainly be a vacuum leak...or not

drjackmd · Post by **drjackmd** » 26 Apr 2016, 09:16

Hey! Yes! I cleaned the MAF sensor. I checked the housing and seating and all looks good. These codes may have been present longer. I dont have a check engine light on, but if I plug in my diagnostic tool it shows those same three codes after a day of driving. Not sure what to look for.