Contaminated MAF sensor L81 2001

Oct 31, 2005 1 Replies
O

I've been trying to find the source of the DTCs P0171, P0174 (Lean mixture on both bank 1 and 2)



Found this TSB 02-T-48



Comes down to that the MAF circuit is energized for a short time after key off. Any oil fumes that back up into the manifold can poison the sensor membrane



The codes can be from a vacuum leak, low fuel pressure or bad O2 sensor. haven't been able to find anything else so I'm springing for the new MAF. Local garage said don't go with aftermarket on this and is getting me an oem sensor for $107.



Got to get this cleared up for NY state inspection shortly. Hopefully this is the fix but wonder when it will happen again?



Oppie


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O

Amazing, the new MAF did the trick! Friend at the garage got me the replacement from Saturn and gave it to me for his cost of $93. Put it in, pulled the controlls B+ fuse for 20 seconds (since I didn't have the scanner to reset the codes). Key on for 20 seconds without starting to calibrate the baseline and start. Let idle for a few minutes and drove off. All is back to normal: good power, transmission shifts properly and the trac light stays on. The trac light had gone off when the ECM threw the codes originally. I'm a happy camper.

My friend cautioned that the MAF on these cars *is* a wear-out item. Some will go 70K and others will fail at 15K. Unlike some MAF units I have seen that have a burn-off circuit that will heat up the sensing element and burn off any contaminants, this one is a thick film sensor and evidently can be poisoned by hydrocarbon fumes.

Oppie

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