• | 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. |
The electronic brake control module EBCM) activates the valve relay to supply voltage to the valve solenoids. This voltage is referred to as the system voltage. The EBCM activates individual valve solenoids by grounding the valve solenoid control circuits.
• | Ignition ON. |
• | The ignition voltage is greater than 10 volts. |
The EBCM is commanding a valve solenoid to release brake pressure. The wheel that is commanded to release brake pressure has a speed less than 5 km/h (3 mph) for 1.25 seconds.
The pressure change of the accumulator indicates the volume of fluid used which is compared to expected fluid used during a brake apply. Too much fluid usage indicates a leaking circuit
• | The EBCM disables the antilock brake system (ABS), traction control and the vehicle stability enhancement system (VSES) for the duration of the ignition cycle. |
• | A DIC message and/or a warning indicator may be displayed. |
• | The condition for the DTC is no longer present. |
• | The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles. |
Antilock Brake System Schematics
Control Module References for scan tool information
Ignition ON, verify that DTC C1120 or C1121 are not set.
⇒ | If the DTC is set, replace the brake pressure modulator valve. If the DTC resets, replace the EBCM.. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for EBCM replacement, setup, and programming |