02 LIBERTY SPEEDOMETER FAILURE.

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Hello. Am a new user, and besides trying to figure out how to post a tech question in the right area, have a problem with the speedometer on my 02 LTD w/V6. It stopped working. The dealership scared me off with the warning that this sort of problem can take hours to trace. I then went to a local garage who deals with a lot of 4x4's, and he hooked up the snap-on code reader computer, and got the error code that is in regards to the ABS system. Unfortunately, this model has no ABS installed. Then cleared the codes, drove it, and received the message "no communication with data bus". The ALDATA program the shop uses then followed the troubleshooting chart, directed us to replace the front input/output speed pickups in the tranny. I did that, and checked all fuses, but still had no speed reading. Next was directed to replace the speed pickup located on the rear axle housing. Did that, and then found a broken wire at the pickup connector. The factory replacement connector didn't come with different colored wires, so attached and inserted into pickup new connector. Still no speed indication, the needle still lays on zero. The instrument cluster self test done by turning ign swith on while depressing the reset button on odometer shows good. Today I'm going to recheck the fuses, swap the wires, and see what happens. Googling the problem last night, also found the suggestions to wiggle any wires going up the steering column, remove, clean and reinstall battery terminals, and look for broken solder joints under the ECU, and speedometer connections. We keep getting the ABS error message for a system that is not installed on this vehicle. Can anyone give some more suggestions?

Gris · **Posted:** Thu Mar 08, 2007 2:01 pm

AUtomatic or Manual trans?

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

It has a automatic trans. Cleaned battery terminals today, no changes in condition.

Gris · **Posted:** Thu Mar 08, 2007 7:31 pm

I'm going through the same thing, but with a manual trans. I'd check the speed sensor sticking out of the top of the rear diff, or the wires going to it.

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Thanks for the info. Did replace the rear end speed sensor, and found frayed/corroded wires at the plug-in from the sensor from wiring harness. Opened up wire loom about 3" in order to find fresh wire to cut. Then installed a new factory clip. Intrestingly enough, the existing wires were 22 AWG, and replacement clip came with 18 AWG, that was 12" long, so this should solve the fraying, corroding wire issues, and I installed some good heat shrink tubing to further protect them from vibration and the elements. As an aside, also found the vent tube breather from rear end to be badly deteriorated, and unfastened from the top clip that holds it in the upright position, and the emergency brake cable going to the rear drum is fraying from rubbing on the upper holder, so I added some chafe protection around it, and probally averted future issues with a damaged cable, wish that Jeep made the stand-off from plastic that wouldn't corrode instaed of the metal one it has. The rear speed pick up looks to be a two wire monopole pick up, so is there a magnet mounted on one of the gears in the rear end? I'm wondering if this interrupter has somehow come off of the gear inside rear end, causing a loss of signal to occur. Hmmm....

Gris · **Posted:** Thu Mar 08, 2007 10:42 pm

There is a "tone ring" in the rear diff behind the ring gear. THe sensor is magnetic. The more quickly the teeth on the tone ring pass under the magnet, the more resistence it generates and the higher your speedo goes.

Mine is still not working but I'm 100% sure it's the wiring for the sensor. I had a spare rear end, so swapped sensors, which did not fix the problem. It seems that sometimes, after releaseing the e-brake, the speedo works until i bounce a little, then it doesn't work anymore.

I'm sure the wiring is frayed, I just can't find where.

Gris · **Posted:** Fri Mar 09, 2007 1:23 pm

yellocoyote wrote:

I just experienced the same kind of problem you had with my KJ. I broke down and took it to the dealer. It's now repaired - the problem on mine was that part of the wiring harness that passes the emergency brake was rubbing, compromising the wires, and giving intermittent power to my ABS system (which I do have). It seems to be in good working order now, but I do plan to get underneath to make sure the rubbing will not be an issue again.

How much did the dealer end up charging you?

I'm trying to decide if I am going to cut teh wires and splice them myself or have a dealer do it.

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

When cutting the wires be sure to make note of the color of the wires because, if you look on the plug they are labled plus and minus. One of the things that I did not do was to differenciate the wires, this might have caused me to not have gotten the signal to the speedometer. The wiring diagram that I have does not show wether or not there is a diode in the system to stop back current. The schematic does show that all leads are to ground, and that should not make a difference, unless inside the signal conditioner there is that diode. The next step will be to reverse the wires and open up the entire wire loom and look for further breaks in the wires other than what was already found. Does anybody know if we can do a continuity check from the plug on top of the rear end to where it terminates on the body wiring harness? :?:

LiLredLibby · **Posted:** Sat Mar 10, 2007 11:55 pm

WEMUNDY wrote:

When cutting the wires be sure to make note of the color of the wires because, if you look on the plug they are labled plus and minus. One of the things that I did not do was to differenciate the wires, this might have caused me to not have gotten the signal to the speedometer. The wiring diagram that I have does not show wether or not there is a diode in the system to stop back current. The schematic does show that all leads are to ground, and that should not make a difference, unless inside the signal conditioner there is that diode. The next step will be to reverse the wires and open up the entire wire loom and look for further breaks in the wires other than what was already found. Does anybody know if we can do a continuity check from the plug on top of the rear end to where it terminates on the body wiring harness? :?:

This is your next step.You need to have the shop with Alldata,print you wiring diagrams, and connector veiws.By knowing wich cavities the speed sensor wires enter the ECU,should able you to do a continuity test for a possible open in one of the wires.If they won't do this for you,PM me and I'll try to get these diagrams for you,as I also use Alldata where I work.Assuming you have an open wire,(which is what I would bet on)more times than not,I'll usually will look in areas such as gas tank straps,crossmember mounts,ect.Also,if the wires to this circut route anywhere near the battery,you might also find that corossion from a sulfated battery may have damaged these wires.Keep us informed on progress and or findings,and holler if we can do anything that might help.

Ron

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Hello again. Shop nearby are great guys, they printed out the schematic for the speed sensor pickup, but it is too vauge to determine if it is the computer on the driver's or passenger's side of the Jeep, and which block contains the offending circuit. They also concur that wringing out the wiring is the best bet. Unfortunately, with current work schedule will not get a chance to get under the vehicle until late Wednesday, got a new set of environmental connectors, and will redo that connection, though I see no diode shown, it could still be inside of the computer box, as the computers are only showing the logic circuits, not the actual wiring diagrams. Stay tuned, I'll update this by Thursday as the saga continues....

Gris · **Posted:** Mon Mar 12, 2007 9:07 am

I tried one last thing this weekend before I give up and go to the dealer.

I cut the 2 wires about 6" from where they join the main wire loom back there. I took the plug apart, resoldered everthing back to gether with new wire and still have no signal.

Dealer is going to be pissed when they see that, but now I have no more options but going to the dealer

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Hello again!

Sorry for the delay in finishing this thread, but ran into some problems with the web site here, and the guys finally got me back up and running with a lot of hard work, thanks again!

The speedometer failure has been corrected. Here's the steps I took:

1. As per ALLDATA, ran the trouble codes on my ODB II code reader, and found the codes leading towards the front trans case speed input/output sensors. Replaced sensors, still no speed/odometer reading.

2. Read OBD II reader again, the previous code disappeared, and was given a code for antilock brake motor failure, plus rear speed sensor pickup. Since there isn't ABS on this model, cleared the code, installed a new rear speed pickup sensoe on top of the rear end housing. While removing the wireing harness clip, found corroded wires at the clip, and a broken connector.

3. Replaced wire connector with factory part. Still no readings. Went back under rear, and with a volt/ohm meter jumpered sections of wire all the way up to where the bundle passes into the frame. That whole section of wire was removed, and a new section of heavier wire with environmental seal connectors installed, and this corrected the problem, and now all is well.

4. I cut open the removed wire, and found three breaks with numerous strands corroded heavily the entire length of the run from the body exit loom to the sensor. I strongly advise anyone with this problem to try splicing in a jumper wire, and see if that works, that would have saved me $100 worth of sensors that never needed replaced, and the $35 wire clip would have been self evident in any case. I looked at my friends '04, and the wire isolation was no better than is mine, so a blob of clear RTV sealed up the gap at the clip that let the salt get into the loom.

Finally, thank you to all of the people who responded with so many great offerings of help, it really is a great bunch of people who are on this site.

Rock On!

LiLredLibby · **Posted:** Mon Apr 09, 2007 7:13 pm

Good job WEMUNDY......I knew you could do it.It becomes a challenge,but thats why I chose this profession.And just to think that this is just the tip of the iceburg as to what I face on a daily basis.Thanks for sharing the outcome,as you have satisfied my curiosity.

Ron

renegadekj · **Posted:** Mon Apr 09, 2007 9:58 pm

Yeah i have to admitt the newer vehicles electrcial schematics can be a confusing challenge even for myself as a industrial electrician. I must say great job troublshooting the problem!

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Hello again!

Have embarked on a new project on the Liberty. Noticed that during dusty conditions the cabin air comes in unfiltered, and found on this website a solution for it by cutting a piece of a/c filter, and attaching it to the airbox inlet screen. Since sheetmetal work & fiberglassing are involved with my line of work, am experimenting with a replacement air inlet box with a regular filter media that will directly bolt inplace of the factory assembly, and allow for easier changing of the filter media. If anyone is also pursuing this line of thought, let me know.

Have a safe day.

jcphoto20 · **Joined:** Sun Nov 19, 2006 1:36 am **Posts:** 507

great job!

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Hello cyberspace again!

Just got all squared away, and was working on a proto-type airbox when I found the pressure line from the power steering pump that runs to the cooler in the front leaking badly, has anyone changed one? It looks like the grill comes off to access the solid lines, appears they run behind the headlight, maybe into the wheel well, any suggested short cuts?

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Found the broken hose. It turned out to be the high pressure line from the pump to the steering box. That required removal of the front grill, bumper, and headlight support valance. The rupture occured about 6" from the pump side fitting, and no apperant chaffing occured, so the hose failed internally. Will have dealership order parts Monday, but am at a loss as to how to re-engauge the fender flare "clips" as Chilton calls them, to remove the clips, prying up and out on the fender worked, but reversing the process seems difficult, any suggestions? :?:

Phadeout · **Posted:** Sun Apr 29, 2007 12:35 pm

Any one have a picture of where the Wires are rubbing and causing this failure? I'd like to check mine before anything happens.

Thanx!

WEMUNDY · **Joined:** Thu Mar 08, 2007 1:28 am **Posts:** 11

Sorry, I didn't take any pictures, but if you look on top of the rear end, there is a connector plug pointing straight up. On my Jeep, the wires were bent at 90 degrees to the driver's side, then another 90 degrees forward. The first break occured right at the plug where the wires went into it. Due to the bend, the environmental seal was compromised, allowing the salt/water/slush mixture to penatrate into the plug. After time, vibrations began snapping the corroded strands of wire, until it reached a point that the current could not pass through them. As an extra problem, the salt/water/slush somehow was wicked up into the individual wires, and using my volt/ohm meter found inconsistant readings all the way up to where the wires pass into the body. I replaced the entire length of both the wires, installed a factory replacement plug, added heat shrink to give a more vibration & environmental seal, then made sure that no exposed wire was to be seen. So far, so good. I examined another Liberty someone has at work, and found his plug to be in the same condition of a hard bend, and exposed wires. Since his was an '06, and hadn't seen salt coated roads, I adjusted the bundle by hand, then applied clear RTV to ensure an environmental seal. His exam and preventive maintenance took less than five minutes, even with jacking up one side to allow easier access to stick my hand up there. Good luck! :lol:

02 LIBERTY SPEEDOMETER FAILURE.

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