Circuit Description
The system relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids and to the precharge pump motor. When the relay contacts close, the EBCM monitors the voltage supplied to the valve solenoids and compares this voltage to monitored ignition voltage.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0201 Antilock Brake System (ABS) Enable Relay Contact Circuit
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
Either of the following conditions may cause the DTC to set.
| • | The EBCM detects that the voltage supplied to the valve solenoids is less than 65 percent of monitored ignition voltage for 50 milliseconds. |
| • | The EBCM detects that the relay contacts do not open when the relay is not energized. |
Action Taken When the DTC Sets
| • | The EBCM disables the ABS/TCS/VSES/DRP. |
| • | The ABS indicator turns ON. |
| • | The traction off indicator turns ON. |
| • | The message center displays the service stability system message. |
| • | The brake warning indicator turns ON. |
| • | The message center displays the service brake 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
Refer back to the diagnostic table, steps 3 through 7, if this DTC continues to set intermittently.
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 | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the DTC reset? | -- | Go to Step 3 | Go to Diagnostic Aids |
Does the resistance measure within the specified range? | 0.3-1.0 ohms | Go to Step 4 | Go to Step 6 | |
4 | Use a DMM in order to measure the resistance between the high side of the pump motor and a good ground. Does the resistance measure less than the specified value? | OL | Go to Step 6 | Go to Step 5 |
5 | Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 7 | -- |
6 |
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 Control Module References in Computer/Integrating Systems for replacement, setup, and programming and the BPMV, refer to Brake Pressure Modulator Valve Replacement . Did you complete the replacements? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
