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Emiss Maint light came on. 89 MJ. 

I see multiple threads that are old and some closed.  Some state that the light comes on based on reaching 80,000 miles.  I just past 75,000.  Some speak of O2 sensor. Some state it is does not really know if the O2 sensor is bad or not.  Other threats state that some O2 recalls are still open and free.  Would someone pull all of this together? How do i turn off the light?

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It is a "feature" in RENIX (87-90) Jeeps. Since RENIX has no OBD or check-engine light a mechanical emissions timer under the dash causes an "Emissions Maintenance" light to come on to remind you to replace the O2 sensor, clean the EGR valve and passages, etc. It serves no purpose other than to turn the light on after a set time period. Your's came on a bit early it appears. I think the dealer might be able to reset the timer, but am not sure. Most folks just pull the bulb or unplug the timer.

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I don't have a Renix, but if I did I would probably replace the O2 sensor if the original is still installed. Use a Mopar or NGK replacement. If you don't know if it's the original or not I'd still replace it, even if there are no apparent emissions problems. How's it running? Does VA have emissions testing?

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Hornbrod asked?  How's it running? Does VA have emissions testing?

 

It runs fine.  I have had the 89MJ for 2 years. Purchased with 57K miles on it. Now 75K miles.  Only northern Virginia test for emissions control.  I am in Virginia Beach; eastern/southern corner of the state.  After reading the posts here, i googled and found all said that it could not be reset but could be replaced.  One person said that replacement would cost about $45 and be good for another run of 80K or whatever it was intended to run.  After your comment I think I will replace the O2 sensor and the pcv which other sites indicated is what the light intended.

 

 

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2 hours ago, Manche757 said:

After your comment I think I will replace the O2 sensor and the pcv which other sites indicated is what the light intended.

 

No PCV on your 89 MJ. The 4.0 and 2.5 have a Crankcase Ventilation (CCV) system instead. Just keep the inside valve cover and tubing clean and the orifice open to help prevent blow-by. THIS article is for an HO system, but the Renix is similar. 

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I know that because I was getting blow-by (oil into my air cleaner) on my 91 when I first got it. Found a tech article online that detailed how to upgrade the CCV system by using the larger 97 and up XJ CCV hoses and metered orifice elbow. Unfortunately this tech article is long gone, but Cruiser's tips should have something on it for your Renix. If he doesn't chime in do a search for "renix ccv system upgrade".

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On 8/10/2018 at 7:04 PM, Manche757 said:

Hornbrod, how do you happen to know all that? Where should I be looking?

 

There are guys on this forum ( HOrnbrod, cruiser, eagle, and Pete among others, certainly many more) who are walking encyclopedias of Jeep. Their knowledge, and willingness to help, are exceptional.

 

Gene

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15 minutes ago, omega_rugal said:

 

shouldnt by now ALL have turned on?

 

Yes, but there might have been a few owners who actually went back to the dealer when the light came on and had both the O2 sensor and the timer replaced.

 

The timers can be reset, too. The FSM only says to replace it, but search the Internet and there are how-tos that describe resetting it. (I just removed the bulb from my cluster.)

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