My check engine light keeps coming on...then it will go away when I shut the car off and restart it. Then it will come on again later. I've been driving my hybrid now for 3 months now (3k miles) and all of a sudden it's doing this. It seems to run just fine so I'm not sure what's going on here. I haven't had a chance to take it in to see what code it's throwing, but it's starting to get annoying. Any ideas? Bad O2 sensor.

BTW, it's a '94 B18C1 w/61k.

 

If its been fine for this long, its probably something simple like the O2. But just think: in the time it took you to post this, you could have checked the damn code already! also, whatever code it is, try resetting the ecu first thing. Sometimes that will kill the trouble code.

 

You know what? That's exactly what's happing to me! After the CEL comes on, I left it on to try to check the code, but it didn't work. I couldn't pull a code out of it. I put in a B18C JDM engine in my 95 EX coupe. I can't seem to figure out why that thing comes on, after a couple of minutes of driving. PLEASE let me know what you find out...

 

is your knock sensor wired up. i had that problem when my knock wasn't hooked up. it would come on after a few minutes of driving. and sometimes it wouldn't come on...

 

knock sensor would still throw a code ... code 23 to be exact. Two things could be wrong:
1) your check engine light could be messing up (?)
2) you could have a bad ecu (or possibly just the led?)

try to deliberatly unhook a sensor, such as the idle controll valve or something, and see if the computer gives you any codes at all. If not, might be your ecu...

 

Do you have an exhaust with a removed cat?.... With my last car and a full exhaust, when I removed my cat... the O2 didn't build enough heat, causing it to throw the CEL on. Just a food for thought.

 

This sounds about right. I don't have a cat. Only thing is that I wasn't getting a CEL for 2k miles since the swap until now. ??!!

Hmm... The hybrid still seems to be running good though.