Description and Operation: Abs/TCCM

The ABS/TCCM is integrated with the hydraulic control unit. It houses the solenoids that operate the hydraulic control unit's input and return valves; the valve stems locate into the ABS/TCCM's solenoids. There is no electrical connection between the ABS/TCCM and the hydraulic control unit.

The ABS/TCCM constantly monitors the brake electronic system by passing self-checking electrical pulses around the circuit. The self check procedures carried-out by the ABS/TCCM are listed below:

1. Monitoring of the operating voltage: the control module will shut-down should the voltages not be (approximately) in the range of 9 to 19V.
2. The pump is monitored for voltage supply and voltage feedback.
3. Monitoring for disturbance, where a failure may be caused by external radio frequency interference, internal leakage current, defective valve transistor or a faulty valve.
4. Internal controller failure, detected by a RAM and ROM test.
5. The controller area network (CAN) micro-controller checks for correct operation of the communication network and performs a RAM self-check.

   Signals processed by the ABS/TCCM are also sent to the CAN for vehicle use, such as the instrument cluster speed display, cruise control and stability/traction control.