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emissions timer

sprinkler1228

sprinkler1228

NAXJA Forum User
Location
Raleigh,NC
I know this has been discussed but I have a question. I have a 91 and I'm trying to locate the emissions timer box to unplug. I crawled under the dash and found a smokey box with a wiring harness going in one side and another coming out the otherside. I'm not sure if this it cause it sounds like it should only be a couple of wires and one plug. I must also mention that its velcroed to the back of the dash just under the knee plate lip. I doubt its orginal location. Does anyone have a picture or has anyone unpluged theirs? If it is it do I unplug both sides? Do I plug the two harness togther and elminate the box?
 
Last edited:
I don't think you have an emissions timer. The Renix models had a timer to indicate when the O2 sensor is due for replacement. The 91 and newer have OBD-I on-board diagnostics. Not certain, but I thought that supplanted the timer.
 
On my '88 XJ it was located right above the yellow cruise control module (on the right side of the steering column. It was about 2"x2"x1". It was made from tinted plastic and you could see a whole bunch of white round plastic gears inside of it. No pictures - I threw it away.
==
While at a junkyard, I saw another one in the same spot, but the plastic was not clear (you could not see inside of the box).
 
Found this:

et1.jpg



et2.jpg
 
Thanks I'll take a look again tonight. What I saw had wires on both sides. I'm not sure what it is so I'll look again and take a picture. But thanks for the help
 
Eagle is correct. On vehicles with OBD-1 (and that's what's in a 1991 model), the timing function to turn on the "Maintenance Required" light is done in the ECU, NOT in a separate timer module, as is done on the older Renix systems.

This light comes on at about 80K miles, to remind the owner to have the O2 sensor changed.

There are two ways to fix the light, once it comes on:
1. using the Chryco proprietary DRB scanner through the diagnostic port to instruct the ECU to reset the timer
2. remove the lightbulb from the instrument panel. (And be sure to remember to change the O2 sensor every 80K miles)
 
If what you found has two wire connectors, one on each side, and it is velcroed to the knee panel, it is your windshield wiper relay/delay module which is to the left of the CCR and typically black.
 
Finally gave in just took out the bulb. I still don't see where you would connect a scanner to reset the computer. I don't think its necessary I will just replace the O2 sensor soon.
 
The connector for the scanner is just behind the ECU on the left fender and is square looking. It is sticking out from a wire harness. It is not under the dash. You need an OBDI scanner to hook into it. Then the reset can be made.
 
sjx40250 said:
The connector for the scanner is just behind the ECU on the left fender and is square looking. It is sticking out from a wire harness. It is not under the dash. You need an OBDI scanner to hook into it. Then the reset can be made.
Click to expand...
OBD-1 scanners are proprietary to each brand of automobile. Thus, you would need a Chrysler-specific scanner to "talk" to the OBD-1 system. Chryco calls it a "DRB Scanner". It is NOT the same as the later, standardized OBD-2 scanners that are available at most auto tools suppliers

Since most of us DON'T own a DRB, the best route is to take the bulb out.
 
AZ Jeff said:
OBD-1 scanners are proprietary to each brand of automobile. Thus, you would need a Chrysler-specific scanner to "talk" to the OBD-1 system. Chryco calls it a "DRB Scanner". It is NOT the same as the later, standardized OBD-2 scanners that are available at most auto tools suppliers

Since most of us DON'T own a DRB, the best route is to take the bulb out.
Click to expand...
I don't think that's exactly correct. OBD-I was the first generation of on-board diagnostics that were intended to make diagnosis of vehicle problems easier, faster, and more precise. There are lots of scanners that will READ Chrsler OBD-I codes.

Resetting the emissions timer, however, is different from retrieving a trouble code. Even the new scanners that will READ OBD-II codes won't reprogram the PCM in OBD-II vehicles. That's where manufacturer-specific instruments come in. For that you are correct, Chrysler calls theirs DRB and that's what is needed to reset the emissions timer. But you would also need the DRB to set anything on an OBD-II compliant Jeep.
 
sprinkler1228 said:
Its agreed I yanked the bulb. Its better to replace the sensor and pull the bulb than get anywhere near a dealership.
Click to expand...
until you go to an independent garage, and they screw it up so bad, and charge you for it,then you need to go to someone that can fix it.
 
Well... maybe. I bought a 92 a couple of months ago. Thought it ran well. Discovered a number of burned out bulbs in the dash. Replaced them and guess what! The engine maint. light came on. I then discovered, on this great forum, what to do about it. I had 4-5 codes triggered.

I found a friendly semi-local mechanic who had 17 years with DC and Jeeps before opening his own shop. He checked everthing out for me. Turned out non of the codes were valid any longer. Once you fix the problem you need to clear the code. Now I know everything is alright. But more important, I will know when something goes wrong and I can find out without tearing the dash apart to be able to get the code. Once I know the code, I can a avoid a few embarrising questions on this forum of highly expereinced people.

I have checked some of the other forums out, and technically, this is the best! and always worth the wait for a response. BTW: don't forget the search button.
 
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