My 90 integra has been lighting the check engine light for a couple of weeks now, but it only seems to come on every now and then. When I get it home and check for a code, there is none. I’m wondering how to figure out what is going on to cause the light. When I turn the key to the on position without starting the car, I do get a single quick blink when the ECU gets power, but it does not repeat. Am I correct in thinking that this is not an actual code, but just the ECU turning on? Thanks in advance for your help.
you are jumping the service connector when attempting to retrieve the code(s), correct?
I thought there was no need to run a jumper on a 90, since it is OBD0
Correct, for OBD0, just look at the LED when you switch your key to the “on” position. At normal operation your ECU should have no light. If you are reading your code correctly, then you have code 1 which is:
Oxygen sensor or circuit
crazy. i didn’t even know that. cool
OK, so that single blink when I turn the key is the code. I guess it’s time to go change an O2 sensor then. Thanks.