DTC U0121: Lost Communication with the Anti-lock Brake System (ABS) Control Module: Description

The PSCM monitors the HS-CAN messages when the ignition has been on for more than 5 seconds, the voltage to the PSCM is greater than 6.5 volts and there are no DTCs present inhibiting PSCM operation.

• DTC U0121:00 (Lost Communication with the Anti-lock Brake System (ABS) Control Module: No Sub Type Information) - This DTC sets when communication between the PSCM and the ABS module fails. For a list of the messages sent to the PSCM from the ABS module, refer to the Network Message List in Description and Operation in POWER STEERING SYSTEM . If messages are missing for more than the allotted time, DTC U0121:00 is set.
• DTC U0121:02 (Lost Communication with the Anti-lock Brake System (ABS) Control Module: General Signal Failure) - This DTC is set when communication between the PSCM and the ABS module fails and the PSCM does not receive the vehicle lateral acceleration message from the ABS module.
• DTC U0121:08 (Lost Communication with the Anti-lock Brake System (ABS) Control Module: Bus Signal/Message Failure) - This DTC is set when communication between the PSCM and the ABS module fails and the PSCM does not receive the vehicle braking or vehicle speed messages from the ABS module.
• DTC U0121:87 (Lost Communication with the Anti-lock Brake System (ABS) Control Module: Missing Message) - This DTC is set when communication between the PSCM and the ABS module fails and the PSCM does not receive the vehicle braking qualifier, vehicle braking counter or vehicle speed counter messages from the ABS module.