I have conducted extensive search here and made repair attempts without success.
2004 v70 2.5t

Last night after returning home, I pulled in driveway and I noticed rough idle while in park. After a few moments of acceration in park, CEL came on. I shut engine and went in for the night.


Today I scanned codes with OBD scanner which has been helpful in the past, however no codes detected.


Symptoms are rough idle while in park. Engine very jumpy, CEL on.
After searching forum, I installed new MAF and checked all coil packs with no luck. I also unplugged battery for a while and no change.


Any indication on what the problem might be?


Recent maintenance: TB, Serp Belt, New PCV system, clean throttle body and replace gasket, new radiator.


I have noticed the throttle body is humming quietly after engine turned off and key removed. Don't remember if it always did.
Please help if you can, thanks!


-Rob

 

could be the airflow meter. Symptoms very similar to when mine failed, find a mate with a car the same and swap, see if problem goes away.

If not and both cars now exhibit same fault it is the airflow meter and will need to reset the fault code.

unfortunately many aftermarket OBD scanners will not pick up the airflow meter fault..........

throttle bodies on earlier cars were replaced under warranty for a manufacturing fault (call it 2000-2002) so could be an isolated failure for similar reason.
good luck

is this why they call it "volvo for life" -once you bought it you're stuck with it!