pcmhacking.net

Hey guys,

I'm working on a April 2008 VE commodore V6 with 4 speed transmission. It uses an E77 engine ecu and separate TCM on RH A pillar.
The vehicle was fine until it sat for months and had a flat battery. After charging it up again and getting it going it is now stuck in 3rd gear, engine ECU reports no communication with transmission module, and scan tool will not connect to TCM.

I have removed the TCM and confirmed battery power to pin 32, ignition power at pin 31, and good earth to the big terminal (forget what number it was).

I'm leaning towards a faulty TCM but before I commit is there any other power/earth requirements that should allow me to communicate with this module?

Also I've never replaced one of these before. Are they common to fail? Are they part of the security system like a lot of other modules, or can I chuck a second hand one in?

Cheers

I believe the ABS (ECBM) is in the data line prior to the TCM?

I could have sworn all 4 speeds where controlled via the ECU and only 5 speeds had a TCM...

TCM is between the ABS and BCM.
Car doesn't start with TCM disconnected but does with it connected, so I'm assuming the data is getting through (or it wouldn't start at all, ECU wouldn't be able to reach BCM).

Hmmm, my diagram says different...

A57 - TCM
A16 - ECBM
A191 - Head light level
A35 - ECM

Is A11 BCM?
If so it seems the same (between ABS and BCM)

A11 - Multifunction control module

It was a faulty TCM. Second hand one fitted and all good. Its not a security module and didn't require linking.

Ha! That’s exactly how I mark dud modules after removal

Yeah those T42 TCMs are really prone to failing these days. I dont know why but they are. I keep a few in stock these days. Be aware though, even though VZ and VE V6 Share the same TCM ( Different partn numbers though) They are not cross programmable. They do brick if you load a VZ OS on a VE and vice versa.
They are used in the VZ V6, VZ LS2, VE S1 LE0 with the 4L60e or 4L65e