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1990 Jeep YJ Wrangler Check Engine Light (CEL) Fails to Come On


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So this is a wierd one, I've looked and looked on the Internet and can't figure it out. My jeep wrangler runs and drives just fine but there is no cel on start up. I know there should be code because I have no 02 sensors hooked up. I want to know if there is more though. Any help would be appreciated

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ventriel...I re-titled your topic post and placed it here at the Jeep YJ Wrangler forum for better exposure.  

The Emissions Maintenance Timer may be involved with your problem.  The Emissions Maintenance Timer is dependent upon the oxygen sensor(s).  If the sensor has been taken off-line, this would effect the Emissions Maintenance Timer.  A defective emissions maintenance timer or disconnected wires at the device could be the reason you're not getting CEL signals.  Someone may have tried to turn off the Emissions Maintenance Timer by disconnecting it or modifying wires.

Check the Emissions Maintenance Timer and its wiring behind the dash light (at the dash panel to the right of the accelerator pedal).   Sounds like a combination of troubles related to the O2 sensor disconnect and the Emissions Maintenance Timer.  These devices are "interdependent".  The timer comes on every 82,500 miles, and it cannot be reset.  It must be replaced or disconnected.  Many owners tamper with the device in an effort to turn it off.

Moses

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ventriel...No box-like device under the dash, either?  Sounds like someone removed your Emissions Maintenance Timer...Disconnecting the O2 sensor would add to the issue...Let us know how you remedy this.

How well does the engine run with the O2 sensor not hooked up?  That should put the system in limp mode...

Moses

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