Transmission limp mode, 2.8crd 2006

[Loker88]

Hi All,

I'm new on the forum so please forgive me any mistakes,

I'm fresh owner of the jeep Cherokee kj 2.8crd, 73k miles, jeep has been used on the farm previously, it's RHD model. I bought it for off roading with a few bits to tidy up and automatic transmission in a limp mode.

Transmission P52119462AG RFE 462, with overdrive mode.
Transmission doesn't change the gears, changes between R and D are sound like a bang/hit.

After diagnostic testing fault codes appeared p0613, p0605, p0700.

Diagnostic tool shows that transmission is in 2nd gear, doesn't matter if you switch to reverse, neutral, Parking, 1 and 2, it shows 2nd. It doesn't change the gears in D mode. Same gear is in 1&2 mode( probably 1st).

I Have checked connectors, wires, grounds. All seemed good.
Replaced TCM, code p0613 disappeared.
Replaced ECU, didn't make any difference
Oil looks clean and levels are fine.

I noticed noise coming from transmission, somewhere were it is connected to the engine.

Also from very beginning trans temp sensor showing -19 Celsius all the time, doesn't matter if is warm or not the temp stays the same all the time . The voltage is around 2.5v when is cold and is going down when warming up. Is this normal ? Is there any chance to cheat the TCM with a resistor to make TCM see temp example 50 C degrees ?

What else I can check before I through the jeep off the cliff please ? After weeks of trying fixing it I'm slowly giving up.

Thank you in advance.

 

[KJowner]

Hello and welcome, I have a similar 04.
It's an RFE 545 transmission, loads of information about them online they were very popular in the US.
Sounds like it's not connected to the TCM, check the wiring and connections.

 

[Loker88]

Hi, I already checked all connectors, wires, grounds, didn't found anything wrong, I think I'll check it again wire by wire.

Is this possible that gear selector will cause that diagnostic tool shows 2nd gear all the time even in reverse and parking?
Thank you

 

[KJowner]

I don't know, but I'd Google some information and test proceedings for the gearbox and work through it, hopefully it's an easy fix.

This is the sort of thing-

https://atracom.blob.core.windows.net/bulletins/2010/aug/atb1336.pdf

 

[Loker88]

That's very helpful I'll check it out tomorrow,

Thank you

 

[Loker88]

Here is little update,

I done the test using instructions from the link,
Jumping pins 15 and 56 makes TCM relay click and it pass all the battery supply to the pins mentioned in the instruction.

What I noticed when engine is running there is battery supply on the pin 15 but TCM control relay doesn't work, there is no power on the pins 16,17,36



It means pin 15 should connect through tcm relay pin 16,17,36 to the supply but for some reason doesn't do it ?

I'm going to feed pin 16 directly from battery with fused wire, I will see if it helps

Thank you

 

[KJowner]

Looks like the TCM may be faulty. Or the wiring harness?

 

[Loker88]

I got two tcm,
One doesn't feed pin 15 when car is running, other one does.

I feed pin 16 externally but it doesn't help.

The very strange thing is happening with pin 15 In power distribution center.

Engine running, multimeter voltage test
Pin 15 to negative on the battery ~13V
Pin 15 to ground in PDC 0,07V
Ground to negative on the battery tested - connection.
Bypassed ground directly from battery, then ~10,5 V

I think the pin 15 TCM gives very poor supply

 

[KJowner]

Strange, are you checking the voltage with the gearbox plugged in or disconnected? I'm wondering if something in the internal wiring is pulling the voltage down.

 

[Loker88]

Plugged in, can't start engine when unplugged as park/ neutral sensor is in the gearbox unless I start the engine and unplug it when is running