MtnGoat

I've changed the O2 sensor and would like to clear the ECU.
What is this procedure?

Been searching here and the web.
Tried a few different ways and haven't been successful.

Its a 92 4.0

Thanks

93_xjcherokee

I just take off my battery cable for a few minutes then put it back on.

MtnGoat

I've pulled the batt cable and left it for over an hour.
With the lights left on and the ignition switch in ON and again in ACC positions.
Codes haven't cleared yet.

Maybe over night?

Ooblar7

I'm pretty sure codes won't clear unless you start er up. Someone correct me if I'm wrong

Tim Rhyne

It's an OBD1 system, so if the light is still on (especially after startup), then there is still a current issue (probably emissions related). OBD1 is an archaic system, so it's a lot tougher to diagnose compared to OBD2. Basically it's a dummy light to tell you there's a problem.

93_xjcherokee

Did you pull up the codes? Cycle the key to run and off 3 times and leave it on run the third time. Count the flashes on the check engine light and that will tell you your problem. I.e. it will flash 2, pause, then 3 or similar.

MtnGoat

I've got an old SnapOn brick to pull codes.

I'm trying to clear the codes.