Check engine light

[driftism]

My check engine light keeps turning on while i am driving along, only catch is that it only turns on when i am on the freeway going up a hill.
This makes me think that it is a problem with load on the engine, but it has oil and water in it and there are no visible signs of a problem when the light turns on. Road speed and engine revs dont seem to change anything, i.e. putting the clutch in doesn't turn the light off, nor does changing gears.

so i am wondering what the triggers for the light are, so i can try and find the cause.

anyone have any ideas?

[Hen is a total nutcase]

Check your ECU for error codes. Maybe it's spitting something. Fix it and reset codes and see if it goes away.

Hen

[parrot]

I put an Jap AE82 twincam halfcut into my wife's old AE82 after she overheated the engine badly. Had been looking for an excuse for ages.

Anyway, that used to do the same thing. Check light would come on under load. I have no idea why. I know that the LHD Euro AE86's have a power light and economy light incorporated into the dash cluster which apparently works of vacuum just like an old fashioned vacuum guage. Could it be related to this? I wouldn't think so.

[chapl]

same happens to my car..

under revs going up a hill it turns on.. then take the revs back it would go away, but put your foot down again it would come back on..

i never really worried about it

[driftism]

How do i go about resetting the ecu? just unplug it?

[parrot]

All you need to do is remove the STOP fuse behind the drivers kick panel for at least 10 seconds with the ignition switch off depending on the ambient temperature, the lower the temp the longer it has to stay out. Then stick it back in and the code has been cancelled out of the ECU memory. Or you can just disconnect the negative battery lead which is what I do, though then you need to reset your clock and possibly stereo.

[johnny_08]

i heard its the o2 sensor screwing up

[Blood Child]

just short out the diagnostic plug in the engine bay (it should be a female 2 pin socket that's not connected to anything. just run a short piece of wire from one hole to the other). the check engine light will flash a certain number of times depending on what's wrong. refer to the manual that matches your engine to work out what the codes mean.
but first disconnect then reconnect the negative terminal of your battery to wipe any previous error codes, then run your car for a bit. the check engine light will flash out the error code when the ignition is turned to the on position, regardless of whether your car is running or not.

[Blood Child]

if you don't have the manual or just cbf finding it, this should cover your needs:
detailed instructions on deciphering 4age diagnostic codes.
that site has an abundance of information which i found particularly helpful when doing my conversion.

[Anthony]

Possibly a missing speed sensor?