P0605 MIL on and trouble shifting

I've got an 07 KJ cherokee 2.8 diesel automatic which is throwing an engine light. The engine control unit has code P0700 which pretty much says the trans is requesting the MIL. In the trans control unit it has P0605 internal read only memory error. I read somewhere that the possible causes would be
1. Poor power or earth circuit to TCM
2. Programming
3. TCM itself
I've tried clearing it with a scan tool and doing the old disconnect battery reset (fixed nothing surprise surprise)
It does look like some work has been done previously around the TCM as the harness clips are all broken and there's electrical tape on some bits so that's a bit suspect. Still can't see any obvious rub throughs. If someone has a pinout or wiring diagram for the diesel model KJ that would be much appreciated. Or if anyone has had this issue resolved before is it worth taking to the dealer to check for module updates?

Try looking here:


Service manuals, parts fiches, a couple of CRD-specific manuals.

You can get your car’s build sheet here by entering the VIN:

klc said:

Try looking here:

Index of /manuals/Jeep/KJ

Service manuals, parts fiches, a couple of CRD-specific manuals.

You can get your car’s build sheet here by entering the VIN:

FCA RAM

fcacommunity.force.com

Click to expand...

Very helpful! Thanks

That is a very good link....I use it all the time!

Does not cover the 2007 models but the 2006 Manuals should be close enough although the wiring colors may be different.

Check all grounding points while you are working around there.

Burgermccartney said:

I've got an 07 KJ cherokee 2.8 diesel automatic which is throwing an engine light. The engine control unit has code P0700 which pretty much says the trans is requesting the MIL. In the trans control unit it has P0605 internal read only memory error. I read somewhere that the possible causes would be
1. Poor power or earth circuit to TCM
2. Programming
3. TCM itself
I've tried clearing it with a scan tool and doing the old disconnect battery reset (fixed nothing surprise surprise)
It does look like some work has been done previously around the TCM as the harness clips are all broken and there's electrical tape on some bits so that's a bit suspect. Still can't see any obvious rub throughs. If someone has a pinout or wiring diagram for the diesel model KJ that would be much appreciated. Or if anyone has had this issue resolved before is it worth taking to the dealer to check for module updates?

Click to expand...

Sounds like you could be describing my Jeep and its quirks exactly.. Any update on what you ended up doing to fix those codes? Trying to avoid throwing more money at the wild goose chase of diagnosing and being pointed in different directions by mechanics, dealership won't touch it since its too old to get parts for, so left to my own devices.

If you have a p0700 code then it's worth getting a garage with a scanner that can read transmission codes to see what fault codes are logged. Simple scanners only read engine codes.