PGM/FI

Advanced Diagnostics

DTC U0121: F-CAN Malfunction (Engine Control Module (ECM)/Powertrain Control Module (PCM)-ABS Modulator-Control Unit)






General Description
The controller area network (CAN) transmits/receives multiple signals to/from the multiple control modules simultaneously by using two signal lines (CANH and CANL). When the engine control module (ECM)/powertrain control module (PCM) does not receive the signals from the ABS modulator-control unit via the CAN lines for a set time, the ECM/PCM detects a malfunction and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
No signals from the ABS modulator-control unit via the CAN lines are received for at least 1 second.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC and the freeze data are stored in the ECM/PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.