Pinpoint Test H : C0020:11, C0020:12, C0020:13, C0020:71: Notes
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 a brief period of time. While the pump motor is activated, the ABS module monitors the voltage drop across the solid state switch. The ABS module then 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 Diagnostic Trouble Codes (DTCs).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| C0020:11 | ABS Pump Motor Control: Circuit Short To Ground | This DTC sets in continuous memory and on-demand if the voltage drop across a deactivated pump motor, solid state switch is greater than 0.5 volt 3 times. |
| C0020:12 | ABS Pump Motor Control: Circuit Short To Battery | This DTC sets in continuous memory and on-demand if the measured voltage drop across the deactivated (non-spinning) pump motor is greater than 0.93 volts for 3-5 seconds. |
| C0020:13 | ABS Pump Motor Control: Circuit Open | This DTC sets in continuous memory and on-demand if the deactivated pump motor supply voltage is below a predetermined threshold (approximately 6 volts) for longer than 2 seconds. Or if the activated pump motor supply voltage is less than 7.3 volts for more than 2 seconds. |
| 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. |
Possible Causes
- Fuse
- Wiring, terminals or connectors
- HCU
- ABS module
Visual Inspection and Diagnostic Pre-checks
- Make sure the vehicle battery terminals and cables are free of any corrosion and other contaminants.
- Make sure the vehicle battery terminals are tightened to their correct torque specifications.
- Make sure BJB fuse 7 (40A) and the fuse socket are OK.