Posted: Thu Feb 04, 2010 12:33 pm Post subject: 02 impala codes 403, 405, 440
I am working on a friends car with these codes. 3.4 liter. Where do I start?! Could a plugged cat cause any of these codes? I know there was a recall on cats for these cars. Had a 303 code, changed plugs and wires and code cleared. Any help is appreciated. She has limited income so going off replacing things at will is a no go. Car idles rough but still gets it upon hard acceleration. Has 170,000 miles.
Thanks for any advise.
Thank you for the quick replies. Upon further investigation, the egr is frozen partially open, and the electrical plug on the valve itself is in rough shape. Since a new egr is outrageous in price, I am trying the local salvage yards. Also there seems to be oil in the anti-freeze. Maybe intake gasket?
I disconnected the positive cable for ten minutes then rechecked codes. Still the same four. Cylinder 3 still has misfire. I tested the coil and it was ok. The 303 code came back after about ten miles on new plugs and wires.
Do you have access to a compression tester? If so, pull the front three plugs and do the compression test. If you have any questions about ihow to do a compression test, I would be happy to answer them.
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