C0121

DTC C0121

Test 1-5:

Circuit Description
The Antilock Brake System (ABS) control module uses a relay to control the valve solenoids. When the ignition is in the Run position, the module energizes the relay winding to switch the battery voltage that supplies the solenoids. The module will disable the relay when the ignition is OFF, or a fault is detected.

Conditions for Running the DTC
The ignition is ON.

Conditions for Setting the DTC
^ The control module commands the relay ON, but does not sense battery voltage at the solenoids.
^ The control module commands the relay OFF, and senses battery voltage at the solenoids.

Action Taken When the DTC Sets
^ The ABS telltale turns ON.
^ The ABS control module will disable the ABS, the TCS, and the DRP.

Diagnostic Aids
This relay is inside the ABS control module and is NOT serviceable.

Test Description
The number refers to step number on the diagnostic table.
2. This step determines if the DTC is current.