Re: 2001 Volvo S40
> My daughter owns a 2001 Volvo S40 4 cyl. L4 1.9 liter turbocharged
> approximately 32,000 miles. The check engine light is on: following codes
> noted: PO101 Mass Air Flow or Volume Air Flow Circuit Range/Performance
> Problem. I have changed the air filter, checked the MAF sensor so here is my
> guess: The engine is turbocharged thus increasing the intake volume of air
> vs. a naturally aspirated engine. At times, the turbo can "overboost" the
> engine causing the DTC I have recorded. Usually the turbo "wastegate" opens
> and bleeds the excess air from the system before this can happen, but if the
> wastegate is hanging up, this might be a likely culprit. Where is this waste
> gate located on this particular engine and/or what does this wastegate look
> like? Can anyone help?
Not likely. If the wastegate is stuck and the turbo is overboosting, a
different code is set - (I'm unsure of the number) usually with the
"boost pressure regulation" or similar in the description. In either
case, the boost will be limited to an lower initial value, so you should
notice a lack of power. With your scenario, you should notice lots of
extra power, followed by the engine cutting out suddenly as the
secondary protection cuts in.
My guess is you have a bad air mass meter or a vacuum leak.
Thornhill (near Toronto), Ont.
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)