Normal Operation and Fault Conditions

The ABS module uses an internal solid state switch to operate the hydraulic pump motor.

The ABS module tests the hydraulic pump motor by activating it for 30 milliseconds.

The ABS module monitors the voltage drop across the hydraulic pump motor while the pump motor is being activated. After 30 milliseconds have passed, the ABS module stops applying voltage to the pump motor and monitors the voltage the spinning hydraulic pump motor is generating and the voltage drop across the hydraulic pump motor solid state switch. If the monitored voltages are not within the specifications, the ABS module sets one or more DTCs.

PPT H ABS MODULE DTC FAULT TRIGGER CONDITIONS

DTC	Description	Fault Trigger Conditions
C0020:11	ABS Pump Motor Control: Circuit Short to Ground	The ABS module receives 3 voltage inputs, 1 input is only present with the ignition ON, the other 2 are fused battery voltage. One battery voltage input is for the pump motor and the other is for the hydraulic valves. The ABS module compares these 2 voltage inputs, if the difference between these 2 voltage inputs exceeds a pre-set parameter, this DTC sets.
C0020:12	ABS Pump Motor Control: Circuit Short to Battery	Sets when the ABS module detects an overvoltage condition due to an internal failure of the ECU.
C0020:13	ABS Pump Motor Control: Circuit Open	Sets when the ABS module detects the current for one of the battery voltage inputs is abnormally low, while the other is high. This is usually due to an open ground circuit.
C0020:49	ABS Pump Motor Control: Internal Electronic Failure	Sets if the hydraulic pump motor actual state does not match the commanded state for 30 seconds; pump is running, pump is not running or pump motor relay shorted.
C0020:71	ABS Pump Motor Control: Actuator Stuck	Sets when the ABS module detects hydraulic pump motor is not rotating when it is commanded to run.
C052E:A2	ABS Pump Motor Control Circuit Low: System Voltage Low	Sets when the ABS module detects an undervoltage condition preventing the operation of the power assisted brakes. This results in high brake pedal effort.