75,000 miles and I just upgraded from regular penzoil oil to penzoil synthetic, just after the oil change the check engine light came on and has been on ever since. All the guages are ok and the car is running great. Any ideas why the light would have came on because of the oil change?


Thanks

Penzoil, maybe the car knows its not good for it, haha. Not to beat on Penzoil but they dont have a very good rep. I think it could be a coincidence possibly. The computer doesnt have anything to do with monitoring oil changes. The best thing to do would be to take it to a parts store, they should scan your car for free, and find out what kind of CEL code you are pulling. If you dont have anyone around to do that you could flash the computer. Flashing is a self diagnostic on most newer cars. To make it work: go to your car, put the key in it, turn the key over to 2nd click but dont start, then turn it back to off. DO THIS: ON-OFF-ON-OFF-ON and leave it on. YOU MUST DO THIS WITHIN A 5 SECOND PERIOD FOR IT TO WORK. Now, count the number of times the check engine light "flashes" on and off. The number of flashes represents the trouble code. There will be a short pause between flashes representing the 1st and 2nd digits of the code. Longer pauses are used to separate individual 2-digit trouble codes. EXAMPLE: lamp flashes 4 times, pauses, then flashes 6 more times and stops. This would be trouble code "46" because first "4" then "6" so "46". Now look up the number for the diagnostic trouble code to find the error then fix the problem. If you dont really care because it is just a stupid light you can disconnect the negative battery terminal for about 10 minutes then reconnect it again. Doing this will reset the computer.