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Discussion Starter · #1 ·
I bought the Jeep and it was not working. So I don't when, how, what caused it to stop. I have read that this is somewhat of a common issue on 03-04 Rubicons. Mine is a 04 manual. The odometer works fine so I know its not the sensor. I have ran the cluster test and the speedometer needle moves and stops and at all the test points. I have swapped the the ECM with a known good one, obviously had to have my vin programmed to it. I have had it at multiple dealerships and none even have a Drb scanner to do anything. I have had it hooked it up to a OBD scanner and it reads the speed while driving. Any suggestions on what the problem is? I am thinking there has to be something else that has to be programmed?
 

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Welcome to ROF! You have certainly done your homework. Get the factory service manual and follow their troubleshooting steps. It just dawned on me that model year has a separate TCM (transmission control module) - I wonder if there's something going on with the TCM talking to the PCM. Since this is a new to you TJ, you don't have any idea of what was hacked together by the seller.
 

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Have you checked the wire/sensor on the transfer case? Sounds like you have the cluster covered, but a loose wire behind it can cause a similar condition.
 
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Discussion Starter · #6 ·
I have visually checked it and pulled it out. I would think that if it were not working the odometer would not work. I could ohm the wires to the pcm if I had a diagram.
 

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From your description, the sensor is working, the computer is getting the speed input, but it is not getting from the computer to the speedo. I have not had my dash apart, but it sounds like the connection from the computer that drives the needle is bad. Download a FSM and look for that interface.
 

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Discussion Starter · #9 ·
I agree with with you JKP. Does anyone know if it is different wires that feed the speedo vs odometer? Or is it all on Can Bus? I will see if I can find a manual to reference.
 

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Discussion Starter · #14 ·
I can't answer that. It was a dealership that told me it was reading via OBD. I doubt they compared it to GPS speed. Although, I could hold it dead on 60mph per GPS and see if takes exactly a minute to clock 1 mile on the odometer.
 

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Pick up a Bluetooth OBD reader. Great little tool, and not very expensive.
 

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Rear wiper & overdrive lockout & axle switch pod assembly may be suspect. Disconnecting these items should result in restoration of normal operation of panel illumination, speedometer and shift indicator.
I just came across this while looking for something else. Might be worth a shot?
Do you have speed control and does it work? Engage it and see if it maintains the speed.
 
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