Mechanics

TROUBLESHOOTING GM TROUBLE CODES

2002 Chevrolet Avalanche • V8 4WD Automatic • 138,000 miles

Trouble codes PO131 & PO151 banks 1&2 O2 sensors #1 keep setting a trouble code while hwy driving. Also sets pending codes for the #2 O2 sensors on both banks. I replaced both #1 sensors w/ new OE sensors but codes still come on with heavy accelaration on hwy. Also seems to lack power unless under full throttle. Can you help me with a diagnosis? This is a 2002 chevy avalanche 4x4 w/5.3 liter. It was also recently setting a code for the MAF but I cleaned it and the code has not returned.
Avatar
Skiracer1
February 23, 2011.



If you have that code, check your fuel pressure. It should be 55-61 psi. Then checkyour fuel regulator. Clane the throttle plate with chokecleaner on both sides as they gum up. Also check for a vacuuum leak. Check all hoses air and breather elements for having holes or not connected. These can also set codes.

Hmac300
Mar 15, 2011.