For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC C0121 00: Valve Relay CircuitCircuit/System Description
The solenoid relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids.
Conditions for Running the DTC
| • | Ignition ON. |
| • | The solenoid relay is commanded ON. |
Conditions for Setting the DTC
The EBCM detects no change in voltage when commanding the solenoid valves ON.
Action Taken When the DTC Sets
| • | The EBCM disables the ABS for the duration of the ignition cycle. |
| • | The EBCM sends a serial data message to illuminate the warning indicator/message. |
Conditions for Clearing the DTC
| • | The condition for setting the DTC is no longer present. |
| • | The EBCM 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
Description and Operation Reference
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, verify that DTC C0201 is not set.
| ⇒ | If DTC is set, replace the EBCM. If the DTC resets, replace the BPMV. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for EBCM replacement, setup, and programming |
