Error code U0129

I have an error code U0129 (Not communicating with brake control module), resulting in loss of speedometer and power steering, and obviously no ABS. I have checked everything I can including:
Replace ABS with ECU unit.
Checked power and ground to ABS unit.
Checked CAN supply to ABS (2.6v at socket).
Checked fuses.
Replaced gearbox speed sensors.
Checked all wiring and connections that I can find.

Does anyone have any other ideas as to what I could check next? Am getting very frustrated with this.