Pinpoint Test V : C0020:13, C0020:71: Notes

Diagnostic Overview

C0020:13, C0020:71

Refer to Vehicle Dynamic Systems for schematic and connector information.

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. While the pump motor is being activated, the ABS module monitors the voltage drop across the hydraulic pump motor solid state switch and the amount of current the hydraulic pump motor draws through the solid state switch. If the voltage drop is too high or if the hydraulic pump motor is drawing too much current, the ABS module sets a DTC. After 30 milliseconds have passed, the ABS module stops applying voltage to the pump motor and observes the voltage that the spinning hydraulic pump motor is generating. The voltage generated by the motor indicates how fast the motor is spinning. Voltage that is too low indicates the motor is not spinning freely and a DTC sets.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Conditions
C0020:13	ABS Pump Motor Control: Circuit Open	This DTC sets in continuous memory and on-demand if the voltage supplied to the ABS module is less than 10 volts, if there is an open or high resistance on the hydraulic pump motor circuit between the ABS module and the HCU, or if the ABS module is faulted internally.
C0020:71	ABS Pump Motor Control: Actuator Stuck	This DTC sets in continuous memory and on-demand if the ABS module detects the hydraulic pump motor is not rotating when it is commanded to run.