Why is my check engine light coming on?

[rdsox325i]

I Just replaced my oxygen sensor because i was getting a check engine light and found out it was the EGO heater so i replaced the sensor. Now the light comes on every once in a while maybe once every other day or so, it stays on until i shut off the car then when i turn the ignition back on it is gone for another day. I am lost here is there really somthing wrong (i can't check for a code because the light goes off as soon as i turn the car off) or is there a bad sensor.... the car runs fine. Anyone have this problem or know what it could be ?? Any ideas are appreciated

[rmn]

You should be able to check the code since it gets stored until it gets cleared. Since you have a 92 you should be able to read your code using the pedel method.
Turn key to the 1st position, Press gas pedel 5 times within 5 seconds, the check engine light will flash count the flashes it will be a series of flashes with pauses (like 1 flash a pause, 2 flashes a pause, 2 flashes a pause and 1 flash this would be a code of 1221) count them and post here and someone will be able to tell you what the code is.
Good Luck

[Slick Willi]

i just took my car in and was having a similar problem check all intake things for cracks cuase if cold air is getting in there its setting that light off

if this was of any help just a thought

[heifetz17]

The EGO heater is not the oxygen sensor. It's the heating element for the oxygen sensor. If you changed your sensor, then your heating element is still bad, hence the CEL.

[Turbo331is]

Actually, the EGO heater is part of the O2 sensor. I also had a 92', and had the same problem. The code you get is for the O2 Sensor Heater Relay. I replace it twice, and still the same problem. Following that I changed to O2 sensor after finding out the heating element is in the 02 sensor. It heats the O2 sensor to 500F to get accurate readings. If it doesn't work, your CEL will come on, and your car will be hesitant until you get it warmed up. It was fine for a day or two, but then it would come back on, and then off. I couldn't retrieve and codes, either from the pedal method or at the dealer. A friend and I used his wrecked car and traced the wire all the way from the O2 sensor to the ECU. It is four wires going to the relay, and then two wires and a ground going to the ECU. There is nothing else for you to replace, and replacing the entire wire isn't feasible. I looked at all Technical Service Bulletins, and no luck there either. It seem's to be happening on a lot of 92's. Its like there is an electrical gremlin somewhere in the wires. I also traced the entire wire with a short finder, and there wasn't one, so there is no way it is bypassing the relay to warm up. I am in mechanics school, and I nor my teacher could understand it. I don't know about your car, but mine was way down on power as well. I replaced plugs, coils, everything, and nothing changed. Sorry I couldn't be of more help.

Wes