C0020:13

Diagnostic Routine V

Diagnostic Overview

C0020:13 or 71

Refer to Wiring Diagram Set 42 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The ABS (Anti-Lock Brake System) module uses an internal solid state switch to operate the hydraulic pump motor. The ABS (Anti-Lock Brake System) module tests the hydraulic pump motor by activating it for 30 milliseconds. While the pump motor is being activated, the ABS (Anti-Lock Brake System) 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 (Anti-Lock Brake System) module sets a DTC (Diagnostic Trouble Code). After 30 milliseconds have passed, the ABS (Anti-Lock Brake System) 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 (Diagnostic Trouble Code) sets.

DTC Fault Trigger Conditions






Pinpoint Test

1. CHECK THE ABS (Anti-Lock Brake System) MODULE PUMP MOTOR (PMP_MOTOR) ACTIVE COMMAND

1. Ignition ON.

2. Using a scan tool, toggle the PMP_MOTOR active command ON and listen for the ABS (Anti-Lock Brake System) pump motor noise.

Does the ABS (Anti-Lock Brake System) pump motor run for approximately 2 seconds?






2. CHECK FOR FAULT REPEATABILITY

1. Using a scan tool, clear the ABS (Anti-Lock Brake System) module DTCs (Diagnostic Trouble Codes).

2. Drive the vehicle at speeds greater than 20 km/h (12 mph).

3. Bring the vehicle to a safe stop.

4. Using a scan tool, carry out the ABS (Anti-Lock Brake System) module self-test.

Are DTCs (Diagnostic Trouble Codes) C0020:13 or 71 retrieved?






3. CHECK THE ABS (Anti-Lock Brake System) MODULE GROUND EYELET AT THE CHASSIS

1. Ignition OFF.

2. Remove the bolt retaining the ABS (Anti-Lock Brake System) module ground to the vehicle.

3. Clean the body mating surface and ground eyelets.

4. Position the ground eyelets and install the bolt.

5. Ignition ON.

6. Using a scan tool, clear the ABS (Anti-Lock Brake System) module DTCs (Diagnostic Trouble Codes).

7. Drive the vehicle at speeds greater than 20 km/h (12 mph).

8. Bring the vehicle to a safe stop.

9. Using a scan tool, carry out the ABS (Anti-Lock Brake System) module self-test.

Are DTCs (Diagnostic Trouble Codes) C0020:13 or 71 retrieved?






4. CHECK THE PUMP MOTOR VOLTAGE SUPPLY TO THE ABS (Anti-Lock Brake System) MODULE

1. Ignition OFF.

2. Disconnect ABS (Anti-Lock Brake System) Module electrical connector.

3. Measure:





Is the voltage greater than 11 volts?






5. CHECK THE ABS (Anti-Lock Brake System) MODULE GROUND CIRCUIT FOR AN OPEN

1. Disconnect the battery negative cable. REFER to Battery Disconnect .

2. Measure:





Is the resistance less than 3 ohms?






6. CHECK FOR CORRECT ABS (Anti-Lock Brake System) MODULE OPERATION

1. Ignition OFF.

2. Inspect the ABS (Anti-Lock Brake System) Module electrical connector.

3. Repair:

- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

4. Connect the ABS (Anti-Lock Brake System) Module electrical connector. Make sure it seats and latches correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?