jeep cherokee -02 3.7 P0500 fault

[cleaf]

i have changed sensor what is located in top of the rear diff.

fault it still on? i have checked wires too and they looked ok.

i did measure ohms on old sensor and new sensor but meter shows 0ohms so are both sensor broken?


speedo doesnt work.

 

[cleaf]

i did remeasure sensor and got some readings.

old one 3Mohms
New 0,439Mohms.

 

[Billwill]

OK I have not looked up that code yet...will do so now.
I presume that your speedometer is not working so you replaced the sensor on top of the rear diff?

Or do you have ABS issues?

The leads going to that sensor on top of the rear diff are known to scrape against the cables for the Parking Brake or against the chassis underneath. Also the connector to the sensor may look like it is on firmly but actually needs some re-plugging.

My Export 2002 2.5 CRD had the speedo stop working when still fairly new. I found that the sensor on the rear diff was not firmly plugged on so I re-plugged it. Speedo worked right away but the CEL light stayed on for about a week of stop-start diving actions at which time the CEL went out!

I believe the diff sensor may be a Hall Effect Sensor ie. a sort of transistor that switches when a magnet goes past it..the teeth inside the Diff ...so a normal Ohm meter will not make any sense.

I have checked the P0500 code and it definitely calls out the diff sensor...If your speedo is working but CEL stays ON then it should reset itself after about a week of driving!

My May 2002 Export 2.5 CRD Manual came with drum brakes at the rear and no ABS.
Six months later they came out with disks at the rear and with ABS hence my query as regards ABS!

 

[cleaf]

sensor has been replaced.

ABS light is on when you start car and speedo doesnt work.

checked to continuity from sensor to abs module with multimeter "beeper function", cables also seems to be ok.

it doest give any fault codes now but still speedo doesnt work and abs light comes on...

 

[cleaf]

https://www.rockauto.com/en/moreinf...dHQ6T1EJeBrXzPq83T3ijLOPHIIx+rebv9NbFPWC3ux4A <--this is new sensor

 

[Billwill]

ABS light should not come ON when starting the Jeep....should only come ON once the Jeep starts moving forward.

Must be wire shorting somewhere, most likely at one of the wheel sensors where the wiring can scrape on the moving hub and go to ground.

I believe on the early KJs like yours that the ABS works by making use of the sensor on the Diff and ABS sensors on some of the wheels....I will read up on which wheels have them on the 03 KJ but you can visually confirm which wheels have them fitted.

You can download the 2003 Jeep KJ Service Manual here...will give you the Theory on how the ABS works and section 8W has the wiring diagrams.

www.colorado4wheel.com/manuals/Jeep/KJ/

OK I have just read the 2003 Jeep KJ Service Manual sections 5 and 8E.

I was wrong when I stated that you should not get an ABS light come ON before the Jeep starts moving. The ABS control unit has 2 processors inside it and these talk to each other as soon as ignition is turned ON. If the two processors have a disagreement with each other then the ABS light is lit. Also when the Jeep starts moving then other checks are done which likewise lights up the ABS light. Definitely download this 03 manual and read up on the theory of operation.
Your Jeep has ABS sensors on the two front wheels and the rear wheels ABS system is operated by the sensor on top of the rear Diff.

Looks like a bad sensor somewhere or bad wiring....you will need to check the wiring carefully for shorts to engine/chassis and use section 8W to trace the wiring.
Once you get into the wiring diagrams I will advise you on how to go about checking for shorts/breaks in the wiring!

 

[cleaf]

finally i did found where problem was, abs control module was "burned". changed it to new and jeep rocks again!
thanks for the help!

 

[Billwill]

Great! Was the ABS Module physically "burnt" or did you just discover that it had failed by swapping it out?

I do not have ABS on my early 2002 Export CRD...came out about 6 months later here and is the one feature that I do miss..... having had ABS fitted on some of my previous vehicles!

 

[cleaf]

Great! Was the ABS Module physically "burnt" or did you just discover that it had failed by swapping it out?

I do not have ABS on my early 2002 Export CRD...came out about 6 months later here and is the one feature that I do miss..... having had ABS fitted on some of my previous vehicles!

Havent opened old module yet, just did replace old one to new and it did the job.