Last spring one of the restraints on the abs lead from my left front wheel faild and the wheel rubbed a big ol raggedy hole in the lead which of course shorted out and took down my ABS system. I replaced the lead and followed the service manual diagonostics which indicated the control module was bad. I bought a brand new module and since I don't have a way to program the new module, I left my jeep at the dealer. The dealer installed the module and could not get the module to re-program. The error message, according to the technician, says the "module is not communicating with the bus." Before I send the jeep back to the dealer for at least $200.00 more work does anybody have an idea of what went wrong?

Vitals are:
2006 Jeep Liberty, CRD, 62,000 + change miles

it sucks that they give you the new 'modules' and you have to have them re-program them! Although it costs money I would have had the dealer do the whole thing....they probably just charged you and didn't want to program a part that they didn't make money on, so they told you it didn't work. can you return the part?

Do you really need ABS?

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Civilisation exists by geological consent, subject to change without notice. -Durant

There may be a wire burned through. The message the technician is getting is the module is not communicating with the bus, so the module will not program. There is a good possibility when the lead shorted a wire suffered an overcapacity of electricity. I was a little miffed the technician didn't call while the jeep was on the diagonostic machinery, I would have had him troubleshoot the problem, good customer service. I can get some help with the part, it is a new mopar part. If the dealer won't help me the part vendor said they would stand by it.

And, with the ABS system down the traction control is also disabled. Its already snowed and the traction control is pretty nice on icy roads which are coming way too soon.

To diag a module thats not communicating, first check power and ground to the module, then bus voltage at the module. if all are present then the module is bad (not likely with a new part).

The reason it needs to be programmed is because the same module is used in different models of vehicle. Then its programmed to match the model and options that it is installed in.

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Resurrected 2005 Liberty Sport CRD
Canadian DRL mod

CRD Motor/Timing Pics
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Here's the latest and this is a truly a sad story.

I re-tested the module according to the service manual and checked for a loose wire etc could not find a thing wrong. Took it back to the dealer after two days of diagnostics he found the abs controller was ok but I had a bad wheel sensor on the rt front wheel, replaced it and still could not get a sensorr signal on the rt front wheel. Next he tried switching the sensor from the left wheel and still could not get a signal. His conclusion is the tone wheel in the hub is bad. It was working before the old sensor shorted out. Could an electrical surge cause a problem with the tone wheel?

I am having the dealer repalce the hub.

stranger things have happened but I've never seen a tone ring just go bad for no reason!! It's a machined piece of metal...unless you smack it off of something and it shatters...it should work. If there isn't any excessive rust or any chipped or missing teeth....the tone ring should be fine. And aren't the liberty ones inside the hub so you can't even see them?? Strange....

Did they check by just spinning the tire or by driving.....spinning the tire usually doesn't work, you have to take it for a spin. Also, if the sensor is too far from the tone ring it may not read. I take it you checked the wiring for continuity, right?? when he used the sensor from the other side, he probably plugged it into the right side wiring...still suspect. I would have made some jumpers and seen if the sensor from the other side would work still hooked to the other side. I say this because with the type of wheel sensors in the liberty (active sensors) they need to have a reference voltage from the control module or they don't do anything!!

Did he do this diagnosis while performing test drives or not?? With the active WSS ABS you need to have it hooked to a scan tool and do test drives to diagnose the WSSs.


Strange things happen when these new fangled computers they put in vehicles have shorts.....

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Civilisation exists by geological consent, subject to change without notice. -Durant

Thanks for the input, it is much appreciated.

My expenses now total $1500 + change ($700 in parts, 2 new hubs and a control module). The OBDII code is a consistent U0121 Lost communication with anti-lock brake system (ABS) control module. I can clear it with my code reader and sometimes it will clear itself. Once cleared I may get 45 or so miles before the code will show up again. I wish I was watching the technician do the tests. The invoice did say he took it for a test drive after he cleared the codes.

I was getting some noise that sounded like a bad bearing from the front end about 5 months before the lead shorted out. I couldn't trace which side the sound was coming from so I changed both hubs. I didn't use Mopar hubs. The dealer changed out the rt front and I changed the left front yesterday with a new Mopar hub. It did seem to help. I took the jeep out for a shakedown cruise. I am still getting the check engine light and the same code. Except I don't get the ABS light.

One strange indication occurred once in a while. The bell, sounded several times, ABS, BAS, red Brake, ESP, Check Engine and traction icon would light up the speedometer and tach would drop to 0 then come back to life again. The ABS related lights and check engine light would remain and the scan code would be U0121. NO other scan codes would show up.

The service manual points to updating the ABS module. The technician was supposed to do that, I am not sure how confident I am that happened properly.

Any thoughts?

Any scan tool recommendations? Many more trips to the dealer and I could pay for a pretty decent scan tool.

Update 12/29
Another trip to the dealer, the tm indicated the ABS's may need to be programed (code u0121). The dealer has the "ability to program" the module, so I am $ 165.89 closer to poverty. When I dropped off the vehicle at the dealer, the multi warning light with the 0 speet and 0 tach. event occured and the dealer saw lots of codes. I didn't get a list but I was told the serial number did not match, vehicle configuration invalid, vehicle and the computer could not see 3 of the four ABS leads. The dealer report states "loss of bircuits needs can C bus." I am wondering if I have a broken wire or maybe a crack in a circuit board somewhere. Although temp does not seem to be a factor. By the way when I picked up the jeep there were no warning lights, they did come on about 30" min later after several stops for errands.

Shirschi,

Did you ever get your issue worked out?
Looks like i'm having the same or similar problem.

There are voltage issues on the main communications bus leading to the inability to program a recently replaced ABS module.
They also just replaced the clock spring as it was thought a lack of steering wheel position information was preventing the ABS module from being successfully programed.

Dealer right now is going through a procedure of selectively shorting different parts of the comm bus to try to isolate the problem.
Right now i have no ABS, Traction Control, or cruise control.

-Mark

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Onward and upward!
2006 Liberty 2.8L CRD

What is your location and is this 2006 CRD a manual or automatic?.....you do get manual 6 speed 2006 CRDs in the Export market!

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2002 Export CRD 2.5 Sport