ABS light on, Tripometer and Odometer don't work

Gabe Watt · **Posted:** Thu Dec 30, 2010 10:59 pm

I have an 05 KJ CRD with 86K on it. No tunes or real mods, bare bones stock. Cruise control works, horn works, and no other lights are on. My code reader doesn't read ABS codes.

I have done some reading and it seems like some faulty wiring or some really dirty wheels might be my problem, and I'm going to take a look tomorrow. But has anyone ever heard of this before? The Jeep drives just fine, stops and starts no problem. Just kinda confused.

warp2diesel · **Posted:** Thu Dec 30, 2010 11:44 pm

Pull your codes and see if you have a bad ABS sensor or bad wiring to a sensor. Code should tell you which one(s) are not sending a signal.

CATCRD · **Posted:** Fri Dec 31, 2010 12:16 am

You have one rear speed sensor for the rear axle, being an 05 year. I can make this problem happen at will by excessive rear wheelspin, so it sounds like your sensor on the diff is going out.

turbobike · **Posted:** Fri Dec 31, 2010 10:19 am

Check wiring leading to rear ABS sensor, and to each front wheel sensor. A chafing or broken wire seems to be a common problem.

dgeist · **Posted:** Fri Dec 31, 2010 10:44 am

CATCRD wrote:

You have one rear speed sensor for the rear axle, being an 05 year. I can make this problem happen at will by excessive rear wheelspin, so it sounds like your sensor on the diff is going out.

X2. Mine went out for seemingly no reason in the middle of spring (identical symptoms). The sensor went bad. The rear diff needs to be opened to make sure the pick-up on the diff isn't fouled.

Dan

DOC4444 · **Posted:** Fri Dec 31, 2010 4:49 pm

Yes, when the single rear speed sensor ('05) on top of the the rear diff housing is not communicating, the red "brake" light comes on, on the dash, along with the ABS light. The odometer and factory GPS stop working, but the speedo and cruise control still work (different sensor). (The front ABS still actually works, too.) BTW, very few scanners can communicate with the ABS system. I only have one that does. I think its an Innova 3160, but check my old posts to be sure. 3120 does NOT work for that.

DOC

painemann · **Joined:** Sat Dec 20, 2008 7:02 pm **Posts:** 607

yellocoyote wrote:

Check wiring leading into the sensor on top of the diff as well. I have experienced twice where the wiring has rubbed through, and shorted out. :idea:

Three times for me, super stupid design!

GaCRD05 · **Posted:** Sat Jan 01, 2011 12:44 pm

Happened to me too around 113k miles. Changed the sensor on the diff first, didn't solve the problem. Then I changed the female end on the wire side. That solved it. On the positive side it was a cheap fix, but a bit of a pain to figure out.

tjkj2002 · **Posted:** Sat Jan 01, 2011 1:28 pm

DOC4444 wrote:

Yes, when the single rear speed sensor ('05) on top of the the rear diff housing is not communicating, the red "brake" light comes on, on the dash, along with the ABS light. The odometer and factory GPS stop working, but the speedo and cruise control still work (different sensor). (The front ABS still actually works, too.) BTW, very few scanners can communicate with the ABS system. I only have one that does. I think its an Innova 3160, but check my old posts to be sure. 3120 does NOT work for that.

DOC

For '02-'05 KJ's the speedo is read off the rear diff sensor.The check engine light(or pending code,no light) will be present also and should be the code P0500 or P0501.So if the speedo works it's not a rear sensor issue.

If the red brake light comes on you have a issue with the mechanical braking system,non-ABS related(low fluid level in most cases).

mackruss · **Posted:** Sun Jan 02, 2011 4:19 am

I've had my problem of the ABS and taction control warning lights diagnosed as an erratic right rear sensor error by the dealer. Dealer suggested that they replace the wiring to the sensor from the front ABS module to the rear sensor.

So i now where the problem is and want to do the DIY thing. I've looked at the rear harness from where the harness exits under the rear seat to the sensor and can't find a crimped or broken wire and was wonderng if i should replace the wires from this point before replacing from the front ABS module. Has anyone replaced their wiring
and how as i thought of splicing the existing wires and soldering new wires on so i don't have to remove the pins from the connector at the ABS module and i'm not sure how the wires connect to the sensor at the rear wheel.

dgeist · **Posted:** Sun Jan 02, 2011 9:07 am

mackruss wrote:

So i now where the problem is and want to do the DIY thing. I've looked at the rear harness from where the harness exits under the rear seat to the sensor and can't find a crimped or broken wire and was wonderng if i should replace the wires from this point before replacing from the front ABS module. Has anyone replaced their wiring
and how as i thought of splicing the existing wires and soldering new wires on so i don't have to remove the pins from the connector at the ABS module and i'm not sure how the wires connect to the sensor at the rear wheel.

Mack, although this isn't the same issue as the thread (since the poster has an '05), You can troubleshoot the harness pretty easily. Take a look at the pics I took for my lift pump: http://kj.polter.net/pics/cummins_pump/

You should be able to use an Ohmmeter with one side under the left-rear seat plug and the other on the sensor end (assuming you can get the plug off at the sensor) to check all the wires. I have a hard time believing the harness is bad if a visual inspection showed no obvious rub-points. It's more likely poor contact at one end or the other from corrosion, water, etc. Some emory-paper and possibly some silver (conductive) grease might help.

Dan

Gabe Watt · **Posted:** Sun Jan 23, 2011 1:08 pm

DOC4444 wrote:

Yes, when the single rear speed sensor ('05) on top of the the rear diff housing is not communicating, the red "brake" light comes on, on the dash, along with the ABS light. The odometer and factory GPS stop working, but the speedo and cruise control still work (different sensor). (The front ABS still actually works, too.) BTW, very few scanners can communicate with the ABS system. I only have one that does. I think its an Innova 3160, but check my old posts to be sure. 3120 does NOT work for that.

DOC

So I finally got a chance to work on this yesterday. And I checked all the wires to make sure that they didnt have any rubs or breaks anywhere, and as it turns out, they didnt. But I did unplug the sensor and when I did this the "Brake" light came on, and it was not on before. So I plugged it back in and the light went off. The ABS light is still on, and the Odo still doesnt work. Now I'm really stumped. I guess it is time to go get my ABS codes pulled.

DOC4444 · **Posted:** Wed Jan 26, 2011 9:30 pm

tjkj2002 ,

I am very careful about what I post on this site. When the rear speed sensor is disconnected on our '05 KJ CRD, the speedometer and cruise control WORK. (Odometer and factory GPS do NOT.)

DOC

DOC4444 · **Posted:** Wed Jan 26, 2011 9:38 pm

Gabe,

What you just did (disconnecting plug actuating "brake" light on dash) makes me think (without access to a wiring diagram) that the actual sensor is bad, as opposed to the connector or the harness which goes to it. This would trigger the "ABS" light and cause the odometer to not work, but since there is power to the sensor, this may account for why the "brake" light is not on.

DOC

Gabe Watt · **Posted:** Sun Feb 20, 2011 6:40 pm

Well i just changed out the sensor, and there was no change. I have checked the wiring leading to the sensor and it is good, inside the jeep and under it, so i am really stumped now.

JeepBumm68 · **Posted:** Sun Feb 20, 2011 9:26 pm

Are 2005 CRD reads the speed off of one of the rear abs sensors. no diff housing plug for us. Anyways we have the same problem like you, since we have SFA'ed the libby. But, I am close to getting everything to work. I'll post up when I am done.

MACKJ · **Posted:** Sun Feb 20, 2011 10:04 pm

Gabe Watt wrote:

Well i just changed out the sensor, and there was no change. I have checked the wiring leading to the sensor and it is good, inside the jeep and under it, so i am really stumped now.

Mate,
I had the same problem as you. I found the wiring was squashed about 6" from the plug caused by the handbrake slamming it into my lift pump bracket. The guys at Jeep changed out the female plug which solved the problem. The squashed wiring is still there and working but I re-routed the cable so that the handbrake cables couldn't do any damage or jam the cable.

turbobike · **Posted:** Mon Feb 21, 2011 9:47 am

just an FYI......while this problem is USUALLY related to the rear ABS sensor/wiring......it isn't necessarily the problem. Check the front sensors & wiring, too. I was on the same witch hunt as you. I replaced the rear sensor and the pigtail connecting to it. (oh-and the 1st pigtail I purchased was defective !) Replaced it with a known to be good pigtail (the ohmmeter is your friend.) Still had the problem. Finally checked the front sensors & found wire leading to right wheel sensor was worn thru in 1 spot and grounding out to the frame. Replaced that pigtail and everything works as it should.

tulsa · **Posted:** Mon Feb 21, 2011 1:44 pm

tjkj2002 wrote:

DOC4444 wrote:

Yes, when the single rear speed sensor ('05) on top of the the rear diff housing is not communicating, the red "brake" light comes on, on the dash, along with the ABS light. The odometer and factory GPS stop working, but the speedo and cruise control still work (different sensor). (The front ABS still actually works, too.) BTW, very few scanners can communicate with the ABS system. I only have one that does. I think its an Innova 3160, but check my old posts to be sure. 3120 does NOT work for that.

DOC

For '02-'05 KJ's the speedo is read off the rear diff sensor.The check engine light(or pending code,no light) will be present also and should be the code P0500 or P0501.So if the speedo works it's not a rear sensor issue.

If the red brake light comes on you have a issue with the mechanical braking system,non-ABS related(low fluid level in most cases).

The rear diff sensor in my '05CRD has failed several times and the result has always been a working speedometer and non-working odometer in addition to brake and ABS warning lights.

Gabe Watt · **Posted:** Wed Feb 23, 2011 2:20 pm

turbobike wrote:

just an FYI......while this problem is USUALLY related to the rear ABS sensor/wiring......it isn't necessarily the problem. Check the front sensors & wiring, too. I was on the same witch hunt as you. I replaced the rear sensor and the pigtail connecting to it. (oh-and the 1st pigtail I purchased was defective !) Replaced it with a known to be good pigtail (the ohmmeter is your friend.) Still had the problem. Finally checked the front sensors & found wire leading to right wheel sensor was worn thru in 1 spot and grounding out to the frame. Replaced that pigtail and everything works as it should.

when you say right do you mean the passenger side?

i just checked the front sensor wires and i couldnt find anything wrong, i will try to look more in depth this weekend. but as far as i knew the odometer (which still isnt working, the speedo works and the brake light on the dash is NOT on, just the ABS light) is read off of the rear sensor, not the front. i may just have to bite the bullet and take it to a shop to have them pull the code and help me figure this out.

ABS light on, Tripometer and Odometer don't work

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