Diagnostic Notes

NORMAL OPERATION
The antilock brake control module conducts a valve function test every time the vehicle is keyed On and the wheels exceed 4 mph for the first time. If valve function is verified, the ABS system is enabled. During normal driving, the ABS relay is pulled in every time the brake is applied enabling the valves to function if required. A passive check is conducted by the antilock brake control module to check for open valve solenoids at this time.

FAULT DESCRIPTION
Front right open dump valve and front right shorted dump valve are generated by the microprocessor's detection of an internal low feedback voltage when the front right dump valve is supposed to be Off (Code C1210) or detection of an internal high feedback voltage when the front right dump valve is supposed to be On (Code C1212). Both codes can be generated by the antilock brake control module during the 4 mph valve check or during ABS activation. Once a valve fault is detected, the amber ABS warning lamp is turned On and the system is disabled for the remainder of the ignition cycle. Upon the next ignition cycle, if the fault is not present, the system will function. However, the fault code is retained for 50 ignition cycles.






POSSIBLE CONTRIBUTING COMPONENTS/VEHICLE WIRING CONCERNS
- Open/shorted valve solenoid.
- Open/shorted valve Circuit 498 (PK) between the antilock brake control module and HCU.
- Shorted/open ECU valve driver.
- Defective valve feedback circuit within antilock brake control module.
- Circuit 498 shorted to ground.