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check engine light...again

J

jmeti000

NAXJA Forum User
Location
san antonio,tx
well, i asked about this a few days ago and was told my 87 renix does not have a check engine light.... however i have since then looked it up and it is apparently supposed to. anyways, the darn thing still wont work... it doesnt come on when the key is turned and it wont even flash a code 12 for pulling the codes. i have checked the bulb and socket and they work, and my fuses are all good. i traced the circuit board to the wire that is supposed to provide the power and its not getting any at anytime... does anyone know what would cause this?? is my ecu bad?? anything or suggestions would be great.. thanks
jmeti000
 
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
Click to expand...
If 5-90 say no then there is not one!
 
I think the pertinent question here is: Why do you think you have a CEL? You said that you have "looked it up". Where? The point is that the standard 87 XJ simply doesn't have a CEL. However, this is of concern to you, and for the people on this forum to offer any creative help, they need to know the specifics of why you are convinced you do have said light.
 
i looked in my auto repair manual.. it says 84-89 have a check engine light with the diagnostic terminal on the front fender well. i am supposed to jumper between terminals 6 and 7 to pull the codes via the check engine light after it flashes a code 12 three times. the whole section starts on page 6-14 of my haynes... and if the repair manual is lying please lemme know so i can burn the piece, sue the company, and make millions so i can really biuld one hell of a rock crawler. not only that, but i have this huge ecu on the underside of my dash with 50 million wires coming and going to it...and amazingly if i unplug the stupid thing the jeep wont start... so obviously the big electrical box with the huge circuit board they call the ecu does something... for they person who asked, im lookin at the third light down on the right of the idiot light cluster right where the cover says "check engine light".
 
jmeti000 said:
i looked in my auto repair manual.. it says 84-89 have a check engine light with the diagnostic terminal on the front fender well. i am supposed to jumper between terminals 6 and 7 to pull the codes via the check engine light after it flashes a code 12 three times. the whole section starts on page 6-14 of my haynes... and if the repair manual is lying please lemme know so i can burn the piece, sue the company, and make millions so i can really biuld one hell of a rock crawler. not only that, but i have this huge ecu on the underside of my dash with 50 million wires coming and going to it...and amazingly if i unplug the stupid thing the jeep wont start... so obviously the big electrical box with the huge circuit board they call the ecu does something... for they person who asked, im lookin at the third light down on the right of the idiot light cluster right where the cover says "check engine light".
Click to expand...

The Haynes is wrong. They are notoriously wrong for a lot of things. Somebody either swapped in a bezel with the newer check engine cover on it, or you have a 91 or newer XJ.

The Renix System uses a rare DRB II Scanner that while using the correct cartrige for AMC/Cherokee, it can read Live Data Only. No stored codes.
 
lumpyidle said:
2.8 v-6 chevy engined XJ does use a check engine light, or malfunction indicator light, maybe four cyl. also.
Click to expand...

although I love to bash Haynes books, the manual does say "on 2.8l V6 engines" after it describes how to jumper the terminals for diagnosis. If you've got a V6 (GM primitive OBD-l system) you should get code 12 (no refrence signal to the ECU) when engine is not running and various other codes based on what the ECU sees. If you've got anything else, you will still have the multi-wire diagnostic center under the hood, but the "Renix" ECU used in these applications does not have the capability to store or privide a code for past abnormalities. It's sort-of a trade off-- the OBD-l system tells you where it got "bad" information (but doesn't do much with the info) and the Renix system is designed to react to the "bad" information and correct for it by either adjusting other controlled circuits or ignoring the info if it consistantly reads out of range.

--Shorty

Give me Renix anyday over the GM system!!
 
OBD1 will NOT store fault codes. you have to scan it when the light is on( IE, don't shut it off)
 
ia green96 said:
OBD1 will NOT store fault codes. you have to scan it when the light is on( IE, don't shut it off)
Click to expand...

from past experience, OBD-l will continue to show code until is has been corrected or the memory has been erased from power being removed. I cannot validate this on Jeep specific on board diagnostis, but since the correct method of checking for codes with OBD-l includes the key on and engine off, it would likely present a problem if they were not stored....

is there anything specific to Jeep that makes it dumber than the other GM diagnostics? I'm not tryin' to argue, just don't have a strong understanding of Jeep specific system.

--Shorty
 
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