Self-Diagnostics

SELF-DIAGNOSTICS

Important: The electronic brake control module (EBCM) turns the valve relay off when a diagnostic trouble code (DTC) is set. The scan tool will indicate that the valve relay is off when it is used to monitor the data list. This is normal and should not be considered a malfunction.

Important: For safety reasons it is recommended that the vehicle not be driven with test equipment connected. Exception: for testing of wheel speeds provided the test regulations are met.

The EBCM performs system self-diagnostics and can detect and often isolate system malfunctions. When it detects a malfunction, the EBCM sets a DTC that represents the malfunction, turns ON the ABS and/or the EBD indicators in most instances, and may disable the ABS and/or the EBD functions as necessary for the duration of the ignition cycle.
Once each ignition cycle, the EBCM performs an automatic test when the vehicle speed > 6 km/in and the brake pedal is not actuated or when the vehicle speed > 15 km/in and the brake pedal is actuated. In the course of this test, the system cycles each valve solenoid and the pump motor, along with the necessary relays, to check component operation. If the EBCM detects any malfunctions, it will set a DTC as described above.