U0121 - Fault ( Need Help )

[Damez007]

Hello,
I’ve got a Holden Commodore SS VE Series II Ute 2010

So I’ve had this fault for a while now.
Upon research and other threads, wheel speed sensors and ABS rear loom can spit this fault.
I bought original new parts for both wheel speed sensors and a new loom and had no luck clearing the fault.
I’ve taken the car to an AutoElec and they said the issue was the ABS module as they couldn’t get past it with the OBD3 so I bought and replaced the computer side of the ABS module and they still couldn’t clear the fault
Now I’m stuck.

Any help would be much appreciated!

 

[krusing]

Where are you located ?
As some members may be able to assist, or chime in and may be able to direct you in the right direction/location,

Has the car had a drink ?
As water could be the main contender for the fault.

I have the faults as -
U0121 - Lost Comms With Anti-Lock Brake System (ABS) Ctrl Mod
U0140 - Lost Comms With Body Ctrl Mod
U0156 - Lost Comms With Body Ctrl Mod

I am tipping its the Anti-Lock Brake System (ABS) Ctrl Mod
Check all the Plugs/Connectors as there could be a pin damaged/corroded by washing the motor, and/or under the car,
The ABS loom normally runs down the drivers side, and the wiring could be damaged/crushed under the plastic covers under the vehicle that they installed on the Series 2 (for sound deadening and efficiency)

 

[Damez007]

Where are you located ?
As some members may be able to assist, or chime in and may be able to direct you in the right direction/location,

Has the car had a drink ?
As water could be the main contender for the fault.

I have the faults as -
U0121 - Lost Comms With Anti-Lock Brake System (ABS) Ctrl Mod
U0140 - Lost Comms With Body Ctrl Mod
U0156 - Lost Comms With Body Ctrl Mod

I am tipping its the Anti-Lock Brake System (ABS) Ctrl Mod
Check all the Plugs/Connectors as there could be a pin damaged/corroded by washing the motor, and/or under the car,
The ABS loom normally runs down the drivers side, and the wiring could be damaged/crushed under the plastic covers under the vehicle that they installed on the Series 2 (for sound deadening and efficiency)

Have you had the Brake system opened ?
try bleeding the Brake System ?

Hi mate,
I’ve had the break system flushed and blead by the mechanics on my last service.

It hasn’t gone for a ‘drink’ haha but yeah it’s definitely a wiring issue

I’m located in Townsville

 

[mechanic]

This is a communication fault being detected by the ABS module. There's no fault with any brake sensors or the brake fluid/ hoses.

It could be caused by a bad power or ground to the module, or a bad communication wire between it and other modules (or even within itself).

It may also be a bad power/ ground in another module on the same network and the ABS module is detecting it.

There a low possibility of it being one of the modules, but rule everything else out before condemning these.

Find yourself a diagnostic flowchart for your car and follow the test procedure, or supply it to your mechanic of you don't have the tools.

 

[Fu Manchu]

You can download the VE workshop manual. Links in the document won’t work but the work around is the documents search function.

Enable the side bar in the pdf reader.

https://drive.google.com/drive/folders/1AsaTX7Z7056lseFwr2vroSdQe5wvsBH7

All the diagnostic flow charts are in this. It’s pretty much a walkthrough. Every code is listed.