C0121

VALVE RELAY CIRCUIT MALFUNCTION
The solenoid valve relay supplies power to the solenoid valve coils in the electronic brake and traction control module (EBTCM). The solenoid valve relay, located in the EBTCM, is activated whenever the ignition switch is in the RUN position and no faults are present. The solenoid valve relay remains engaged until the ignition is turned OFF or a failure is detected.

CODE PARAMETERS
DTC C0121 will set if:
^ The solenoid valve relay is commanded On and the EBTCM does not see battery voltage at the solenoid valves.
^ The EBTCM commands the solenoid valve relay Off and battery voltage is still present at the solenoid valves.
^ When this trouble code sets the EBTCM will disable ABS, Traction Control and Dynamic Rear Proportioning and turn ON the antilock and RED brake telltale

DIAGNOSTIC AIDS
^ It is very important to thoroughly inspect wiring components and connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ The valve relay and circuits are internal to the EBTCM. Replacing the controller is the only repair.