Hi everybody I'm new in this forum.

I just bought a 2001 Volvo S40. When its at idle, sometimes the RPM would fluctuate +/- 800 and sometimes it even stalls when its set to park. It had a Check Engine light so upon downloading the codes at the auto shop, they told me I had P0101, P0102, which points to the mass air flow, and P0450 which points to low fan circuit. I'm not sure what it all meant, but basically they said I need a new MAF sensor, and that should clear the fault codes and the stalling at idle problem.

I got a new MAF sensor and installed it. Went to Autozone immediately, cleared the faults, but the engine still rough idles. The check engine light came back on again on the same day, and I still have P0101. I've only changed out the MAF sensor for a couple of days. Do i need to "break in" the part? As in drive the car for a few days first, then go and clear the code? Or could there be another problem? I've observed that the car doesn't stall anymore but the RPM still fluctuates every once in a while.

Thanks for reading!!!

 

There is a hose that goes from the Intake to the Intercooler check that hose good for cracks and leaks.

 

Thanks for the prompt reply!

Is that the rubber hose that connects the intercooler to the throttle body? If that's what you're talking about it looks good.

I've also removed the hose and cleaned the throttle body with a cleaner. It looked kinda complicated so I didn't remove the throttle body just sprayed it as much as I could while getting my wife to step on the gas pedal so I could clean the other side of the plate as well. After all that the stalling has stopped but the engine idling is still a little rough, about 800RPM +/- 200RPM. Is that normal?

Also I've read up somewhere that for the S40, you also have to clean the ETM, which is connected to the air intake from the air filter box. I've tried to locate that, but its like way under the engine and seems unaccessible. Could the ETM be a potential link to my problem as well? If it needs cleaning too should I try to clean it or bring it to the pros?

 

The ETM is an electronic throttle body which your car doesn't have.

The idle is supposed to be about 700 RPM.
You might have a bad enigne mount and it is fooling you into thinking it is running rough.

 

Here's what I've done so far.

Changed the MAF sensor.

Changed air filter.

Cleaned throttle body.

My car no longer stalls when at idle set in Park, but I'm still unable to clear the codes. Basically I still have P0101, P0102 and P0450. What should I do?????

 

You clear them and they come right back?

 

Yup.

 

Double check and make sure you have no vaccum leaks anywhere.

 

You know, this mechanic came by my place today and looked at it. He's not exactly a Volvo mechanic, but he suspects an air leak somewhere, because he said he could hear something. We could hear like an air leak, and it seems to originate from somewhere underneath the air filter box. Are there any vacuum lines located there?

 

I believe one of the intercooler hoses run under there.
Also check the one those that goes from the Idle motor at the intake to the Intercooler by the cooling fan.

 

Brought it to a volvo mechanic and finally found the diagnosis. Tech you are right, turned out its a vacuum leak! They fixed it on the spot, real happy with that.

One advice, don't waste your $$ bringing it to a place like brakes auto, who charge you 65 for an hour and they juz pull the codes but don't really do any diagnosis. They just looked at the code and told me my mass air flow sensor needed changing, and I paid 180 bucks for that. If they had just listened carefully at the engine, they would have spotted the hissing sound. Ah well, lesson learnt.

If anyone reading this is from Phoenix, Tanner Volvo Motors is where you should bring it, they're pretty good.

Lastly, thanks again Tech for helping out!

 

tech is the man here. I do beleive he knows almost everything. No is only someone could help me fix my drive shaft

 

Just to update, there is a Software upgrade for MAF codes that was released on May 7th.

 

Hi All. I have a new (to me) '01 V70 FWD non-turbo. It's been running great the past week I've had it until today. I went to getgas (used premium) and the car wouldn't start.

I google'd it on my Blackberry (I almost got rid the BB) and found out about the immobilzer wire issue. I jiggled the wire and the car started.

BUT, on the way to work, after driving about 35 miles or so, the car started to die out when I would come to a stop. I'd have to put it in Park, start it, it would run ok as long as I gave it gas, put it in drive, etc. I had to do this about 3 or 4 times. Then magically, the problem went away. It would happen when slowly idling down, the the engine would vibrate as I was coming to a stop, then at about 5 MPH, it would die.

Question 1:

My question is, would the immobilizer cable going into the starter cause that to happen because of it being dirty or loose? I'm going to take apart the intake system today and clean the MAF, throttle body and change the filter. I hear no vaccuum leaks.

Question 2:

If I have the vaccuum leak people talk about, is there enough pressure in that system to make it noticable, or would it be so faint I can't hear it?

Question 3: Is it possible the previous owner did NOT use premium as required and perhaps either the computer is relearning the mixture or the intake is really dirty? Again, it's been running fine all week til this morning when I put premium in and the immolizer cable needed to be reseated. It was driving about 200 miles before that and no problems at all.

Thanks in advance! Hopefully I'll make it home from Downtown Chicago back to the burbs so I can take it apart. I'd greatly appreciate any feedback. I'm researching the forum now for more answers.

 

One more note; I noticed the one of the tiny hoses that goes from the top of the air filter cover to the engine was not pushed in or loose at the end that plugs into the engine (I'm not sure what that hose does). I reseated that hose/wire this morning when I was messing with the immobilzer starter cable.

Could that have anything to do with it? Again, I appreciate any help just so I know I can make it back home safely [&o]

 

1.The immoblizer only works on start up. Once started then it is bypassed.
2.Is the check engine light on now? Maybe a fuel pump relay or something like that is going bad.

 

The engine light is not on at all. I took the entire intake system apart and am cleaning things right now. The MAF is very dirty so I doubt it was getting any kind of accurate readings. There is also some valve that opens and closes at the intake side that seems to open and close a tube coming from the exhaust manifold. I'm assuming thats for heating the air? I've never seen this on any intake before.

That part is also dirty so I'm cleaning both with a q-tip and weak alcohol. I've done this a few times with other cars.

Now I have two questions. (sorry)

1. The two small hoses that are on the filter box cover; I removed them before I noted which goes to where. If you are looking down on the lid/box, the one on the right goes to that valve on the intake hole and the one on the left goes to the engine right after the throttle body, correct?

2. The throttle body has the wiring harness screwed into it. Can I just remove the screws and unplug it, or is it hardwired into that plug?

Thanks for the feedback. I ordered the fuel filter yesterday. If this stuff doesn't work, I'll go to the more expensive relay and fuel system stuff.

 

I figured out the hoses by the indentations so that's done. The car doesn't idle up and down anymore. It stays constant. That bypass valve that ported heat to the air box from the exhaust manifold was filthy with dirt and grime. I took that apart to clean it and now it works great. The MAF sensor was also very greased up so I cleaned that as well. I took the throttle body off and cleaned it.

the engine seem to be running fine now. It seems like it's still re-learning that it needs to idle down better when the break is pressed. It has a new Air Filter too.