DTC U0121: Lost Communication With Anti-Lock Brake System (Abs) Control Module: Notes

Fig 1: Communication Circuit Diagram

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

For a complete wiring diagram Refer to SYSTEM WIRING DIAGRAMS .

• When Monitored: 
  • With the ignition on 
  • Battery voltage between 10 and 16 volts 
  • IOD fuse installed 
  • FCM is configured correctly 
• Set Condition: 

  Bus messages not received from the Antilock Brake Module for approximately 2 to 5 seconds  .

Possible Causes 

CAN B OR CAN C BUS CIRCUITS OPEN OR SHORTED

DTCS RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES

FCM NOT CONFIGURED CORRECTLY

ANTILOCK BRAKE MODULE POWER AND GROUND

ANTILOCK BRAKE MODULE

MODULE THAT SET THIS DTC