I have a`97 850GLT ~110K miles. My local mechanic told me that the error code was indicating rich fuel mixture and thatthe AFM sensor was most likely theculprit.
I replaced it (costing me $250 from the Volvo dealer), but the CEL came back afterit was reset.My mechanic told me theerror code had returned (only ~5% rich fuel)and that he needed a couple of days to troubleshoot my Volvo.
By the way,the carruns fine and has no problems, but I need to bring it in forits annual emmison test.
I appreciate your input in advance

Thanks

 

An error code indicating a rich mixture could also be faulty O2 sensors. Do you know what number the code is?

 

Greetings,

If you haven't noticed drivability problem, it is most likely the O2 sensor, as Miatamon has already mentioned (or could also be misfire, I remember one person has reported similar problem and he had a code for misfire). Many people have reported that they've had engine performance problem that was related to the MAF sensor or the electrical wiring to the sensor.

If you can locate a local auto parts store, such as AutoZone, they provide free diagnosis service, so you might want to take advantage of it. Make sure tolet them show youthe trouble code& description on the scanner.

I don't want to put down other professionals, but your mechanic does not seem knowledgeable on Volvo, or modern diagnostic system, judging from the following statement:

>thatthe AFM sensor was most likely theculprit.
If the MAF sensor was the culprit,the ECUshould have reported it with "MAF sensor signal absent or faulty", "MAF sensor burn off signal too low", etc...on a diagnostic scanner/equipment. Guesswork should be eliminated from diagnosing electronic control-related problems as much as possible, though there are still some situations where guesswork is the last resort. But in this particular case, I am curious as to how your mechanic did the diagnosis. I usually recommend people to go either to the dealer or to shops that specialise in Swedish/European makes for servicing Volvos.

Here's a reference:
http://volvospeed.com/Repair/a2.html

The trouble codes may differ according to what engine you have (turbo, N/A, etc...).


JPN

 

Thanks for all of your feedback
I will take it to the AutoZone and find trouble code out then will post it here.
The local mechanicwas usingupdated scanner showing all kinds of graph and they are Europeanspecial shop

 

Good luck.

>The local mechanicwas usingupdated scanner showing all kinds of graph and they are Europeanspecial shop

In such case, the shop would probably be trustworthy.

I wish the problem would be solved this time. Let us know how it goes, if you would.

Best wishes,


JPN

 

I just got back from AutoZone and the trouble code is P0172
I guess my next action will be go after Oxygen sensor but is there anyway I can verify it before I replace it.
Thanks again for your input in advance.

 

IIRC the oxygen sensors can be cleaned sometimes. Maybe it's worth a try before changing them.

 

Make sure you have no vaccum leaks at all!!!
Make sure the hose from the airbox to the turbo is good as well.