DTC U0121-Lost Communication With Anti-Lock Brake Module: Notes

Fig 1: Anti-Lock Brake Module Communication Circuit - Circuit Diagram

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article.

When Monitored:
Ignition run time is greater than 1 second. Battery voltage between 9 and 16 volts. Engine run time greater than 3 seconds.
Set Condition:
The PCM doesn't receive an ABS message over the CAN C circuit for 7 consecutive seconds. The circuit is continuously monitored.

Possible Causes
CAN C BUS OPEN OR SHORTED CONDITION
ABS MODULE
PCM

Refer to ELECTRONIC CONTROL MODULES/DIAGNOSIS AND TESTING for diagnostic procedures and for further possible causes.