Service Engine Soon

[lovnmy2boys]

Just bought a 2001 Aztec just over 40,000 miles. Everyday the Service Engine Soon light has come on. Have brought it back to the dealer that I purchased the car from twice. 1st time put it on his computer and received code 404...said it was possible that the gas that I got the day before had expanded. Reset light. Brought back again and he took it to another garage with better computer. Came back and said nothing showed on computer but light was not on at that time. Does the light need to be for the computer to read it? Also....it is fine each morning as I drive to work. When I come out of work after it sitting in parking lot all day is when the light comes on. Stays on for about 10 to 15 minutes while driving then shuts off. Has done this everyday since I bought it 6/16 except today. Which it did not sit for an extended period of time due to being off from work. Mechanic seems to think it isn't hurting engine but it must be on for some reason...right???

 

[melsg5]

you dont mention what kind of dealer, GM? there is a service bulletin out on PO404 concerning the EGR valve. Try this bulletin number 06-06-04-003D. It uses part number 89018174 to repair the problem

 

[lovnmy2boys]

It was a small local dealer who bought it the week before from the local Pontiac dealer which he says sold it to the 1 owner in 2001

 

[melsg5]

then take it back to the GM dealer with the information concerning the service bulletin

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[lovnmy2boys]

Was told by the GM dealer that the service bulletin was not for my Aztec.

 

[melsg5]

Are you sure about the code? It should start with the letter P. You may try replacing the EGR valve.