Last job was to replace the ABS module to try and solve the rear left locking under braking issue. I thought about getting a second hand unit from a breakers, but managed to find a new OEM module for a decent price:
This is a pretty easy job with the airbox out, take off the 11mm brake pipe unions, unclip the electrical connector and loosen off 2 x 10mm mounting bolts. Same again in reverse:
The tricker bit is purging and bleeding the system using CLiP. Definitely needs a second pair of hands, as someone needs to sit in the car with the laptop and foot on the brake pedal pumping, while someone else goes around each of the four corners bleeding the brakes following the procedure on CLiP. The brake pedal feels much more solid now, I'm wondering whether I've been driving around an issue for a while.
After following the procedure and the pedal feeling great, I was still getting a brake fault when powering up the car and the ABS wasn't working (brakes were great, but locking all four corners):
As this was happening on the pre-ignition cycle, I knew it was either an electrical or calibration issue, and not a physical fault. Took me a while to figure out what it was, as CLiP isn't the most intuitive software.
I was getting two error codes, DF055 (Programming of Vehicle Parameters) and DF020 (Speedo Index Programming).
DF055 was reporting a 2.DEF status, which means it has an invalid program. Poring over the parameters I noticed that PR063 was set to a value of '99':
This meant the module had not been coded to the type of car. This should either be 1, 2 or 3 depending on your make/model.
Once I'd figured out how to edit this value, I changed '99' to '3' (mine is a Phase 2 CUP in this context) and wrote the data to the module. This cleared DF055 error code. I also found out that you need to code the module to your wheel/tyre size. Once I'd done that, it cleared DF020. After another code reset, neither came back.
I make that sound easier than it was, in reality that took me 2hrs+ to figure out, going in and out of various CLiP menus as it's not intuitive at all. Hopefully that sorts out the rear wheel locking issue, haven't been able to go out and test it in anger yet. Fingers crossed.