C0121
CIRCUIT DESCRIPTION
The solenoid valve relay supplies power to the solenoid valve coils in the EBTCM. The solenoid valve relay, located in the Electronic Brake and Traction Control Module (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.
CONDITIONS FOR SETTING THE DTC
^ DTC C0121 will set anytime the solenoid valve relay is commanded on and the EBTCM does not see battery voltage at the solenoid valves.
^ DTC C0121 will set anytime the EBTCM commands the solenoid valve relay off and battery voltage is still present at the solenoid valves.
ACTION TAKEN WHEN THE DTC SETS
^ A malfunction Diagnostic Trouble Code (DTC) stores.
^ The ABS/TCS disables.
^ The amber ABS/TCS indicator(s) turn on.
CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
^ 100 ignition cycles pass with no DTC(s) detected.
DIAGNOSTIC AIDS
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal-to-wiring connections
- Physical damage to the wiring harness
^ The following conditions may cause an intermittent malfunction:
- A poor connection
- Rubbed-through wire insulation
- A broken wire inside the insulation
^ If an intermittent malfunction exists refer to "General Electrical Diagnostic Procedures" in Diagrams for further diagnosis.
^ The solenoid valve relay is an integral part of the EBTCM and is not serviced separately.
TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
4. This step checks for a short to ground in CKTs A291 or A290.
6. This step checks for an open in CKTs A291and A290.