XJ Sam

Alright guys, looking for some help here.

I've owned several Jeeps and XJ's, but I just picked this one up a few months ago.

Airbag light is on and will not go off. I replaced the clockspring today because the horn was not working.

Horn is now working with the new clockspring in place. This was not a used clockspring, I did buy a brand new one.

The more and more I start to things apart on this Jeep, it looks like the wiring has been cut in a few places.

I know the control module is mounted under the driver seat. I found a wire that had been cut. I can double check the color, its a bit dark outside at the moment. I noticed not too long ago that the drive power seat would not move unless the Jeep was turned to the on position (I thought it should work regardless and have a constant 12v)

Anyway, after realizing that, I found a cut wire under the seat. I think it was maybe blue with a red stripe or something. I can double check. The wire was cut and then for some odd reason I traced it back back to the 12v cigarette lighter wire?? Not sure what the previous owner was trying to do here.

Are there any wires specifically for the power seat that when tampered with could cause issues with the airbag system?

Any help on this one would be appreciated.

Thanks
-Sam

captainwoot

Hello, your air bag light can be on for any number of reasons. Your best bet is to find someone with a scanner to read the codes, this will give you a direction to proceed with a repair.

XJ Sam

Agreed.

I will do that if I can't seem to figure it out. I was just fishing for some ideas or possibly other common issues for the airbag light.

I don't have a scanner readily available at this point, so I would have to take it somewhere.

prcherokee

Control module wiring.

CCKen

Good luck.

XJ Sam

Thanks guys.

I did have access to a scanner here at work that reads SRS codes. Going hop outside and scan it really quick and see what codes come up.

Will update here in just a few minutes.

XJ Sam

I think the ACM is where the problem is.

I am going to pull it later today and check the wiring and the connection. Also, inspect the pins and connectors for any corrosion before I replace it.

I hooked the Autel scanner to it a couple minutes ago. It is unable to communicate with the system. Since it's all ran through the OBDII, I ran a DTC test as well just to make sure it was communicating with everything else.

Everything else seems good. No DTC's store or pending. Real time data and system monitors look good. Just unable to communicate with the SRS system. I would assume I have a ACM issue at this point.

XJ Sam

Just and update...

Worked on a few things this weekend. Figured out the reason the power seat was wired to the cigar lighter. As the harness for the power seat runs across to the passenger side and into the harness, I found the wire broken. Solder the connection and all is well. They jumped into the cigar lighter for power instead tracing the bad connection (which was still dumb since it only has power when the key on. DOH!)

I picked up another ACM from CL. I will install that today and see where it leads me.

Another odd issue that has popped up. On my way to work today, the airbag light went off and the CEL came on just before the airbag light went off. I think the only reason the airbag light went off was due to the connection at the gauge cluster. I pushed on the panel and the light came back on. However, I tried connecting the scanner to it when I got to work, but now not only does it not read the airbag module, but it will not read DTC's from the ECU. I get a communication failure. The scanner gets powered KOEO, but will not read anything. It's an Autel AL619. Not the best scanner in the world, but certainly not the worst either.

I'm really starting to get stumped on this one. The only thing I did this past weekend that may have changed something with the DLC connector was re-doing (so to speak) all of the fuses in the fuse panel. Some of the fuses were in blank spaces and some of blank spaces needed fuses. I used the fuse diagram and cleaned it up and put the correct amp fuse in each slot.

I REALLY need to get this thing inspected as I have a rejection sticker on it now. Any help would be awesome. I have heard that sometimes the CPS needs to be disconnected before attempting to read codes on the ECU? Is this correct?

Thanks again everyone
-SAM

CCKen

DLC No Communication:

Here's a diagram that shows the modules that have SCI Transmit and SCI Receive. Refer also to the CCD Data Bus schematic that follows.

If your scanner powers up that should mean that you have power at DLC pin cavity 16 and ground at cavities 4 and 5. The problem with communication sometimes lies withthe scanner, which may not connect to your older DLC SCI Transmit and SCI Receive pins. SCI Receive is the link to the PCM inwhich data from the scanner is sent to the PCM to 'ask' it for CCD Bus data. SCI Transmit is/are the circuit(s) that transmit data to the scanner.

Verify that your scanner can transmit and receive data from your DLC and that the scanner harness connector is the correct one for your DLC. The manual for your scanner should explain the compatibility. Your PCM/CCD Bus is an SAE J1850 protocol. Your vintage Jeep requires connection with the CCD Bus and the SCI circuits. Newer vehicles communicate through SCI circuits (several).

Also, check pin cavities 6 and 7 on the DLC for corrosion and being enlarged, or pushed back, from someone shoving a meter probe in them.

SCI diagram:



CCD Bus Schematic:



~~~~~~~~~~~~

Airbag:

Before working on the ABCM, disconnect your battery negative post connector and wait about 5 minutes before doing anything with the Airbag system.

And, do yourself a favor, remove the trim panel and knee blocker from below the steering column, then unplug the Yellow connector attached to the bottom frame of the dash. This connector (C205) is the quick disconnect link to both Airbags. With it unplugged you should be safe from setting the bags off with an Ohmmeter.

Being mounted under the seat is bad. The ABCM can get ate up with corrosion. If it, and the connector look okay, there could be a problem with the ground for the ABCM. Unfortunately the ground stud is under the carpet and attached to the driver's seat front support structure on the floor.

You can check the ground circuit from the ABCM pin cavity 10 (Black/Pink tracer wire) to chassis ground. If it reads high resistance or open, the ground connection is probably gone south. If this is the case you may want to splice in a new wire and find a new ground point for it.

More than likely, however, the ABCM is defective.

Some connecor pics:





Under center console location, but you can see the ground wire coming from the connector.

XJ Sam

Thanks for the reply.

I was able to get another Autel scanner hooked up to it. AL539. This scanner connected and ran everything fine. I could monitor all of the real time data of the engine when it was running too.

Before started it though, I scanned for codes since the CEL was on. The scanner stated the CEL was off which was odd. I checked for store codes and pending codes on the scanner which turned up zero results. I was going to go ahead and use the erase codes function, but just before I pressed the button, the CEL went off. Not sure whats going on there. I also found it odd that the Autel AL619 connected fine the other day, but today gave me communication failure.

I'm getting ready to change out the ACM in just a couple of minutes. Will update with results once its installed.

Thanks again!

XJ Sam

Changed the ACM last night. All is well and the airbag light went off.

Also threw in some new lift supports while I was working on it. Its nice to have a lift gate that doesn't fall on me every time I open it.

Thanks again for the help. I can get this thing inspected today! Finally.

CCKen

Good work.

Thanks for the follow-up.