CEL on RPMs going up and down

kluchtman · Post by **kluchtman** » 23 Oct 2009, 12:24

Ok, here are the P codes I have listed twice in my 2000 S40.

P0102
P0101
P0171

It sounds as if the engine is trying to stay alive but is being suffocated, but then being allowed to breath and then suffocated again. Anyone have any ideas on this? I am assuming a sensor, but which sensor is the big question.

Kurt

Post by **billofdurham** » 23 Oct 2009, 12:47

P0101 and P0102 are both Mass AirFlow (MAF) related. It may be that the MAF is dirty so the first step is to clean it with a proprietary cleaning spray.

P0171 relates to boost pressure and has possibly been triggered by the other codes as one of the side effects is the initial boost pressure.

Try cleaning the MAF, erase the codes and see what happens.

Bill.

kluchtman · Post by **kluchtman** » 23 Oct 2009, 14:09

Just to be clear, the MAF is the filter on the left side of the engine, right in back of the battery?

Post by **billofdurham** » 23 Oct 2009, 15:36

The MAF sits in the inlet to the air filter. To quote the song "a picture paints a thousand words" this is from the VADIS parts list:

S40 MAF.pdf: (622.34 KiB) Downloaded 199 times

The MAF is part #22.

Bill.

kluchtman · Post by **kluchtman** » 24 Oct 2009, 09:05

Bill,

Thank you very much, that helps a lot! I was thinking of the air filter. Where are you getting the VADIS pdfs?

Kurt

Post by **billofdurham** » 24 Oct 2009, 09:54

I bought the VADIS disc from eBayUK not long after Volvo decided to stop using it.

It has limited use for the older cars but for the S/V40s it has some clear repair instructions with good illustrations. It doesn't cover post 2005 cars.

eBayUK prices are still cheaper than US and most of the sellers will ship to the US. Beware of those who claim you can have free updates for life and charge you a lot more. There are no updates. I haven't seen this on the UK site but it has appeared on the US site in the past.

Bill.

kluchtman · Post by **kluchtman** » 28 Oct 2009, 20:14

Ok, so i blew out the MAF with compressed air, put it back together and the engine was still trying to die. i took out the air filter and tried the car and everything worked just fine. so I got a new air filter but the car still wants to die. To get around my inspection requirement I could take out the air filter, clear the cel and then have it inspected, but I don't want to chance hurting something in the car by doing that.

Any other ideas for me to look into?

Kurt

Post by **billofdurham** » 30 Oct 2009, 13:10

Try cleaning the MAF with a proprietary MAF cleaner available at most parts stores.

Bill.

kluchtman · Post by **kluchtman** » 14 Dec 2009, 18:33

Ok, so it's been a while since I was on here, have been busy with the fam.

I got the MAF cleaner today, took out the MAF and blew it out. Let the MAF dry and then put it back in. Started up the engine but it seems to sputter a bit, the RPM's went down 1 or 2 notches but came right back.

Also I noticed that on my cloth that I had under the MAF as I blew it out, there was a good amount of black / grey specks of dust or something.

Lastly, I disconnected the + on the battery while I did this, in an attempt to clear the CEL. However the CEL was still on when I started up the car. Not sure if the CEL is supposed to go out when I disconnect the bat or not. It did on my S70 but there is a 2 year dif. on my two cars.

If anyone has any ideas on this, I really would like to know. I am actually past my inspection date and need to get this fixed.

Kurt