No Speedo Reading / Wont shift

[bodgie]

Do you have the service manual? If so there are a heap of faultfinding procedures you'll be able to follow to check.

Jason

[oracian69]

A bit more info.

I am now showing ZERO values on the "Transmission Output RPM" field from WJDIAG.

Can anyone confirm that this sensor is INSIDE the transmission on the 2.7 CRD? Im pretty sure it is on the conductor plate....

I can replace this (hassle) but what worries me is the wheel sensors are still all showing 0.

So is the wheel sensor issue causing the OutputRPM issue or the other way around...

[Adrian D]

There's no transmission output speed sensor, it's calculated based on the sensors.

There is a CAN line between the ABS module and the ECU, I would check if that is still ok.

You can find the factory manual here:
http://colorado4wheel.com/manuals/Jeep/WJ/

Schematics are included.

Can you access the ABS module in WJDiagPro?

Some info regarding the ABS to ECU wiring is also here:
https://jeepswj.com/axle-swap/

[oracian69]

Thank you Adrian D, very useful links. Appreciated. I did have an old FSM, but it seems to give way, way less info than the ones youve linked here.

[Mudgee hunter]

I have a back up pcm, but not a perfect match. I can start and drive it to get me home. But I don't get any dash instruments .
My speedo and tacho often play up. I flick the plastic and they bounce back to life.
I have removed it and cleaned the terminals. Bad earth on it perhaps.

[oracian69]

For anyone interested it turns out I had 2 problems.

1. The ABS module (CAB) was bad.

2. ALL 4 wheel speed sensors were faulty/bad. Why I dont know. But I am guessing that perhaps the faulty ABS module perhaps was to blame - maybe it sent too high a voltage to them and "blew" them. I dont know exactly, but the chances of all 4 wheel speed sensors failing at the same time naturally has to be millions to one..

[Adrian D]

Quick, it's time for a lottery ticket

Thanks for the updated on this, it does seem like a really strange failure