Diagnostic Instructions
DTC Descriptor
DTC C0201 : Antilock Brake System (ABS) Enable Relay Contact Circuit
Circuit/System Description
The solenoid and pump motor relay are located within the electronic brake control module (EBCM). The solenoid relay supplies battery voltage to all of the valve solenoids. Three pump motor relays supply battery positive voltage to the pump motor when the
EBCM commands the pump motor on.
Conditions for Running the DTC
| • | Ignition voltage is greater than 9.5 volts. |
| • | The solenoid relay is commanded ON. |
Conditions for Setting the DTC
One or more of the following conditions exists:
| • | The EBCM detects an open in the battery positive voltage circuit to the solenoid valve relay. |
| • | The EBCM detects a stuck open solenoid valve relay or an open circuit between the solenoid valve relay and solenoid valves. |
| • | The EBCM detects an open in the battery positive voltage circuit to the solenoid valve relay. |
| • | The EBCM detects that one or more of the pump motor relays is off when commanded on. |
Action Taken When the DTC Sets
| • | The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Vehicle Stability Enhancement System (VSES) for the duration of the ignition cycle. |
| • | The ABS indicator turns ON. |
| • | The driver information center (DIC) displays the ABS FAULT message. |
| • | The Stability Caution indicator turns ON. |
| • | The DIC displays the SERVICE STAB SYS message. |
| • | The DIC displays the TRACTION FAILED message. |
| • | The Brake Warning indicator turns ON. |
Conditions for Clearing the DTC
| • | The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Antilock Brake System Connector End Views
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
Circuit/System Verification
With the scan tool, access the ABS special functions menu and perform the Solenoid Test and ABS Motor test. The pump motor and solenoids should function without setting DTCs.
Circuit/System Testing
Disconnect the EBCM harness connector. Connect a test lamp to ground, at the EBCM harness connector touch the test lamp probe to each of the 3 battery positive voltage circuits. The test lamp should illuminate on all 3 circuits.
| ⇒ | If the test lamp does not illuminate on one of the battery positive voltage circuits, repair open or short to ground on the suspected circuit. |
Connect a test lamp to battery positive voltage, at the EBCM harness connector touch the test lamp probe to each of the 3 ground circuits. The test lamp should illuminate on all 3 circuits.
| ⇒ | If the test lamp does not illuminate on one of the ground circuits, repair open or short to voltage on the suspected circuit. |
| ⇒ | If no wiring faults can be found, replace the EBCM/brake pressure modulator valve (BPMV) assembly. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for EBCM and BPMV replacement, setup, and programming
