Volvo V 40 has an intermittent check engine light problem

volvo
v40

#1

My 2002 Volvo V 40 has an intermittent check engine light problem. I?ve had it on the diagnostic computer which indicates the air mass meter is the cause but I?ve already replaced it twice.



I?ve also replaced both the front and rear oxygen sensors. My mechanic suggests that the cause may be the fuel pressure regulator but that?s not indicated by the diagnostic.



The check engine light seems to come on when the gas tank is either just filled or when it gets down to below a third of a tank. If it doesn?t come on at start-up it will usually remain off. It doesn?t seem to come on when driving regular speeds. It only comes on at start-up or sometimes when idling.



When it comes on at idle it feels like the engine stumbles a bit then rights itself and the light comes on. Other than that the car runs nicely and has gotten consistently good mileage both city and highway.



Any one out there have any idea what could be causing this.


#2

There is no code that tells you that the MAF sensor is bad. There are several codes that point to the MAF circuit and even then the circuit might not necessarily be the issue but there could actually be an air leak somewhere. There is also no code that would tell you that a FPR is bad, though I wouldn’t be looking at that.

So…the first thing you would need to post is the exact code - Pxxxx

After replacing the MAF this last time did you read the codes again?

Did you inspect the wiring for the MAF? Check the harness? Put a multimeter on it to check its power supply?


#3

Update to: 2002 Volvo V 40 has an intermittent check engine light problem

My 2002 Volvo V 40 has an intermittent check engine light problem. I?ve had it on the diagnostic computer which indicates the air mass meter is the cause but I?ve already replaced it twice.

I?ve also replaced both the front and rear oxygen sensors. My mechanic suggests that the cause may be the fuel pressure regulator but that?s not indicated by the diagnostic.

The check engine light seems to come when the gas tank is either just filled or when it gets down to below a third of a tank. If it doesn?t come on at start-up it will usually remain off. It doesn?t seem to come on when driving regular speeds. It only comes on at start-up or sometimes when idling.

When it comes on at idle it feels like the engine stumbles a bit then rights itself and the light comes on. Other than that the car runs nicely and has gotten consistently good mileage both city and highway.

Any one out there have any idea what could be causing this.

Since I last was on I?ve had the car put back on the computer and here?s what it said: ECM-14 Mass air flow (MAF) sensor- Faulty signal


#4

Since I last was on I?ve had the car put back on the computer and here?s what it said: ECM-14 Mass air flow (MAF) sensor- Faulty signal


#5

A faulty signal might come from a bad sensor. Or it might just come from a problem with the wiring. So the whole MAF circuit needs to be checked out.


#6

Where should I start. After I posted the first message, we went on vacation for a couple of weeks. when I returned the check engine light wasn’t on and didn’t come on until after I had the computer check out the car again. I sent you what the read out said: ECM-14 Mass air flow (MAF) sensor- Faulty signal. At that point the engine light was not on. It did not come on until the next day and is once again intermittent. Now it seems to be coming on less frequently than before we went on vacation.