Check engine light

[dkeeton]

I recently purchased an 89 Sidekick. Everything was fine when I purchased it and as it is to be a hunting vehicle I replaced all fluids as well as plugs, wires, filters and oxygen sensor before taking it out to the ranch. Now my check engine light is on solid. I have checked the chilton manual on it and shorted the appropriate wires under the hood to try and read the code but the light remains on constant and does not provide a code. According to the manual this means the ECU is bad. About every third time you start the vehicle is runs really poorly and misses very bad. The others times it seems to run fine. My question is, might something I have done caused this and is there any way to test the ECU before just purchasing another one?

[DeadSock]

sounds like the milage tripped (did you recently get a 60K 80K 100K 120K milestone?)

search under the left hand side of the dash for small switch (usually behind the speaker, or behind the dash panel below the steering column). Get a good light, an inspection mirror, and happy hunting (I think it took me about an hour to find mine near the steering column).

flip the switch, and you should be good until the next milestone. (If that doesn't fix it, then it may be a bad ECM).

[Crossroads Bill]

Originally Posted by dkeeton

I recently purchased an 89 Sidekick. Everything was fine when I purchased it and as it is to be a hunting vehicle I replaced all fluids as well as plugs, wires, filters and oxygen sensor before taking it out to the ranch. Now my check engine light is on solid. I have checked the chilton manual on it and shorted the appropriate wires under the hood to try and read the code but the light remains on constant and does not provide a code. According to the manual this means the ECU is bad. About every third time you start the vehicle is runs really poorly and misses very bad. The others times it seems to run fine. My question is, might something I have done caused this and is there any way to test the ECU before just purchasing another one?

Might try a new gas cap.Ours started comin on when the gas cap was left off and comes on every now and then after a fill up.It seems to run ok tho,just that irritating light is on