Contaminated MAF sensor L81 2001

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

 

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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