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

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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 10 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. The PSCM receives the vehicle speed signal over the HS-CAN from the ABS module. If the PSCM fails to communicate with the ABS module, the PSCM defaults to a predetermined vehicle speed value and steering assistance is reduced.