Service Engine Soon?
Service Engine Soon? Service engine soon light came on just recently and has stayed on.....I wasn't beatin the car down, or anything...... just drivin down the highway. I had a tech at AutoZone run the tester for me. It ran a code 420. When I asked the dude what it meant, he said, "he had no idea". He looked it up in their little book and came up with a few scenarios...1.catalytic converter failure 2.Major exhaust leek 3.engine predetonation.
How would I tell which of these is wrong? the car runs great, I never smell ehaust, but I'm not sure how to test my cats? NE suggestions? Or do you think I should just take it to the Pontiac dealer n have them check it out!?
How would I tell which of these is wrong? the car runs great, I never smell ehaust, but I'm not sure how to test my cats? NE suggestions? Or do you think I should just take it to the Pontiac dealer n have them check it out!?
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
P0420 is a drivers side cat inefficiency code - usually means cat is bad. GM just extended the warranty on them to 10yrs/120K on the 00-02 cars. If the code keeps coming back I'd leave it stored and contact a dealer for free replacement.
Thanks for the replies gents! I have a 98 t/a w/just over 100k miles.....I just bought it off of some dude on Ebay about 3weeks ago. I don't know anything about the cars history "except from carfax". By looking at the car, I see and HEAR that it has headers and I'd say 3" (oval) exhaust and a cold air intake.
I drove it from KY to WI with no problems "service engine soon". Just all of a sudden the light came on this week while I was goin down the highway. The car still runs great!!
I drove it from KY to WI with no problems "service engine soon". Just all of a sudden the light came on this week while I was goin down the highway. The car still runs great!!
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just have the code turned off. If you find a local speed shop they can prob do it for a fair price. If you are running an ORY pipe or even high flow cats, Correct me if I'm wrong, but even the high flow cats throw codes sometimes. As long as it's one of the rear 02 sensors it's not important. I forget the code my car was throwing but it was the passanger front 02 sensor. If your gas mileage is between 14-16mpg. It's def your front 02 sensor get it fixed ASAP!
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