Circuit Description
Ground is continuously supplied to the low side of the ABS pump motor. The EBCM activates the ABS pump by supplying battery voltage to the high side of the motor.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle speed is greater than 6 km/h (4 mph). |
Conditions for Setting the DTC
The EBCM detects an open pump motor circuit, a shorted pump motor, or a seized pump motor or ABS pump.
Action Taken When the DTC Sets
| • | The EBCM disables the ABS/VSES. |
| • | The TCS operates with engine torque reduction ability only. |
| • | The ABS indicator turns ON. |
| • | The message center displays the service stability system message. |
Conditions for Clearing the DTC
The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
Separate the EBCM from the BPMV in order to inspect for corrosion or any other condition that may cause a poor connection at the pump motor connector. Refer to Electronic Brake Control Module Replacement and Testing for Intermittent Conditions and Poor Connections . If severe corrosion or other damage exists, the BPMV or the EBCM may need to be replaced.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the DTC set? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 5 |
|
Important: Using a test lamp other than that which is approved for performing diagnostic procedures on GM vehicles may cause an inaccurate result when performing this step. It is also imperative that the ground to which the test lamp is connected be clean and provide no resistance to battery ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems for more information. Connect a test lamp between the battery positive voltage circuit to the ABS pump motor, and the pump motor ground. Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 6 | |
5 | Repair the high resistance in the battery positive voltage circuit. Ensure that total circuit resistance is not greater than the specified value. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | 0.2 ohms | Go to Step 13 | -- |
6 | Test the ABS motor ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | -- |
7 |
Does the DTC clear and then remain cleared while the test lamp is connected? | -- | Go to Step 8 | Go to Step 10 |
8 |
Does the test lamp illuminate for 5 seconds and then turn off? | -- | Go to Step 9 | Go to Step 12 |
9 | Inspect for poor connections at the pump motor connector. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
10 |
Important: Following EBCM replacement, perform the set-up procedure for the EBCM and perform the Yaw Rate Reference Table Reset Procedure. Use the scan tool to perform the Tire Size Calibration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
11 | Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
12 |
Important: Following EBCM replacement, perform the set-up procedure for the EBCM and perform the Yaw Rate Reference Table Reset Procedure. Use the scan tool to perform the Tire Size Calibration procedure. Replace the EBCM and the BPMV. Refer to Electronic Brake Control Module Replacement and Brake Pressure Modulator Valve Replacement . Did you complete the replacements? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
