MAINT REQD light on a 91 YJ
 

Ever since I bought my 1991 Jeep YJ (about a year ago) the red "Maintenance Required" light is always on my dash. There's nothing wrong with the Jeep and anything that was wrong was fixed properly. I would like to reset that red light. I am not sure how to reset it, I have removed and re-inserted every fuse but the light stays on.

-Bladdder

Re: MAINT REQD light on a 91 YJ
 

Try disconnecting the battery for 10 minutes ,this should remove any codes in the computor.

Re: MAINT REQD light on a 91 YJ
 

If that doesnt work, pull the bulb out.

Re: MAINT REQD light on a 91 YJ
 

It Needs to be reset using an On Board Diagnostic reader/computer. It only takes a few minutes but dealers may be expensive. The maintenance reminder is for the oxygen sensor. It may be cheaoer to replace it than diagnose the old one. This is pre OBDII Gord

Re: MAINT REQD light on a 91 YJ
 

When you install a new engine part (from the air box to the tail pipe) or even buy a used YJ, it is best to reset the engine computer (ECU). This can be done very simply by erasing the Adaptive Memory. The Adaptive Memory learns about your engine and you’re driving habits during the first 50 engine warm-ups. By erasing this memory, the computer is reset to factory conditions, without resetting the ECU the computer does not know that new engine parts have been installed and will continue to operate on the old information in its memory. On a used YJ you will be driving on the pervious owners habits. To reset the ECU:

1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.
2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.
3. Reconnect the positive cable to the battery.
4. Turn the key to on but do not start.
5. Turn the headlights on.
6. Turn the headlights off.
7. Turn the key off.
The ECU has been reset to factory conditions. For the first 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.

Re: MAINT REQD light on a 91 YJ
 

Only way to reset that light is to replace that little box on the firewall to the right of the gas pedal. It's only a timer that trips the light when the dealer wanted you to bring it in for major service that prob wasn't required. Just unplug the wires from the box and it will go out. I used the wires from mine for the CEL when I swapped in the OBD2 Vortec V6 this year.