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Where is the "Check Engine" light on my 88

S

SoCal88XJ

NAXJA Forum User
Location
San Diego
My 88 has a "Check Emiss" light but no "Check engine" light. Are these one in the same? I pulled the dash bezel and the cover for the lights to the left of the speedo so I could read what all the lights were, as well as replace any bad ones. With the engine off and the key on, I only get a seatbelt light. I have tried the 3 off then on key turns to get the codes to read back but nothing flashes. Any thoughts?

Nothingbelow the clock either, just a blank pad.
 
The Renix ECMs (87-90) do not support a diagnostic trouble light or check engine light.

If I am not mistaken, the emission light is triggered by a module that is meant to be replaced after it sets the light off. I believe it was intended to set the light off about the time an oxygen sensor was due for replacement, thus replacing the module and starting the internal time clock over again.
 
Last edited:
There is NO CEL/MIL (Check Engine Light/Maintenance Indicator Light) on the XJ prior to 1991 - they were "pre-OBD," and did not store or throw codes. I go through this every two years with the smog people (with four RENIX XJ's, that works out to about once every six months. I'm getting tired of it.)

The "Emiss" - Emissions - light is run by a timer which is, I believe, down by the fuze panel. Find and remove the timer, and it's a non-issue (I've removed these timers from my rigs - and I never had issues getting smogged as a result.)

I actually prefer the RENIX system over the ChryCo OBD - unlike most OBD systems, one can do most troubleshooting on RENIX with little more than a decent multimeter - which I have owned for a long time...

There won't be anything under the clock to the right - the "System Sentry" was deleted early on. The clock itself probably doesn't work anymore - I stuck a Velcro pad there, and use it for a utility spot (my stereo remote is there right now...)

5-90
 
My wife was driving my old 88 XJ and that emissions timer fell out from under the dash, right under the brake pedal. She didn't know it had happened and scared the crap out of herself trying to mash on the brake pedal to stop the Jeep.

Or in other words, take it out and you could potentially save a life.
 
90' xj

Just got the jeep home today....havent learned it yet. (new to me)

Where is the fuse box and what does the timer look like? Mines on as well as another light just below that one.

Gotta buy more tools and start asking more questions now have a ton of things to fix.
 
Thank you everyone, you just saved me a ton of money on my car insur... er, uh, I mean an obd I scanner. I'll have to do a little research on the Renix system as I am very proficient with a multimeter/oscilloscope.
 
5-90 said:
There won't be anything under the clock to the right - the "System Sentry" was deleted early on. The clock itself probably doesn't work anymore - I stuck a Velcro pad there, and use it for a utility spot (my stereo remote is there right now...)

5-90
Click to expand...
Sounds like I should have sold you my working clock...
It's now where my sat rad is mounted too.
 
No, thanks. However, if anyone has "blank" panels (no clock) that will fit there and are largely unmarred, I'd like to see about talking you out of them...

After all, if the clock doesn't work, I might as well get rid of the damn thing. I wear a watch - and do you have any idea how long it took me to find decent 24-hour analog watches that cost less than my truck? I can't wear digital...

5-90
 
SoCal88XJ said:
Thank you everyone, you just saved me a ton of money on my car insur... er, uh, I mean an obd I scanner. I'll have to do a little research on the Renix system as I am very proficient with a multimeter/oscilloscope.
Click to expand...
You don't really need a scope. Like 5-90 said, the Renix system is pretty basic; a reliable, high quality DMM is all you really need. But, you do have to study how the system runs, and what role all the inputs/outputs play interacting with the ECM. I too prefer the Renix system over the Chrysler. I'm at the point where I can diagnos everything on it. We can't post links to FSMs and such do to copyright issues. However, searching the internet for the Renix Fuel Injection Manual will turn up what you need.
 
Ditto on the lightbulb in the clock, I just replaced mine. I thought it was broken but now I realize I just can't see it in the daytime unles the lights are one!

AJPulley, thanks for the search criteria - I didn't want to ask considering the forum rules! I'm on it now!
 
Yeah, you should have no check engine light (RENIX). You SoCal go through way to much smog trouble. Move the Nor Cal (Humboldt Co) and you only have to smog when you want to sell.
 
The "check engine light" light assembly was left on the assembly line in Toledo, unfortunately, the rest of the emssions crap usually did get installed. ( I am joking about the light, as everyone has allready posted about it.) As for having a "converter"... Well, around here, a "converter" is something normally used to make solid corn into liquid corn ( REALLY big grin ).
 
5-90 said:
No, thanks. However, if anyone has "blank" panels (no clock) that will fit there and are largely unmarred, I'd like to see about talking you out of them...

After all, if the clock doesn't work, I might as well get rid of the damn thing. I wear a watch - and do you have any idea how long it took me to find decent 24-hour analog watches that cost less than my truck? I can't wear digital...

5-90
Click to expand...
I went to a pocket watch, I tend to break watches worn on the wrist anyway.
I'm going to look at a 90 for parts, if it's got a blank plate I'll snatch it.
 
It's not damage that causes problems with digital - I just blank the displays. I figure I get it from my granddad - he couldn't even wear a watch that took a battery, he'd somehow depolarise the motor in a couple of weeks. I just make displays go blank.

My "everyday" watch lives on an issue watchband - 2" wide Nylon web, fatened with Velcro, and with a "crystal cover" strap. Works nicely - although I did just have to replace the band because it had been through 15 years and four watches...

Since I buy waterproof watches, I'll usually just toss the whole thing into the laundry when I need to clean it - no trouble there.

5-90
 
TGoff, I visit humboldt quite a bit, nice area. I have family on the Ave of the Giants. Down here in South SoCal (san Diego), we have areas that are smog exempt as well, thankfully. You only need to smog once when you buy it and once when you sell it. I'm currently working on the first one and thanks to this thread I'm making good headway with testing all the sensors. Unfortunately, everything looks good except the sniffer at low speed and a low idle at times. My MAP sensor is reading 1.7 volts at idle instead of .5 to 1.5 so i think i might have a leak somewhere.

I picked up my 88 Laredo for $200 with a bad harmonic balancer (typical rubber seperation, found new on ebay for $55). The entire vehicle is bone stock and well taken care of. A s far as I can tell, its only missing leather power seats as far as options. Tow package, limited slip diff, AWD option tcase, power everything else. Runs and drives great - taken over as my daily driver I like it so much. Thinking I might add a little 2.5" lift, swaybar disco's and slightly bigger All terrain tires and call it good to go.
 
haha cool, i was wondering if my check engine light was burnt out on my 87 wagoneer but it seems i have gotten another thing to fix checked off of my list. what all lights are supposed to turn on when i turn the key to the on position?
 
KarlVP said:
My wife was driving my old 88 XJ and that emissions timer fell out from under the dash, right under the brake pedal. She didn't know it had happened and scared the crap out of herself trying to mash on the brake pedal to stop the Jeep.

Or in other words, take it out and you could potentially save a life.
Click to expand...
What does the timer look like? A relay or? (will it look the same in a 90' ?)

Thanks
 
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