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Home >> Mazda >> 2024 >> 3 Carbon Turbo, 4D Hatchback >> Repair and Diagnosis >> Accessories & Equipment >> Infotainment >> On-Board Diagnostics - CMU (2 Of 2) >> DTC U2121-00: Communication Error With Vehicle Control Module (VCM)

DTC U2121-00: Communication Error With Vehicle Control Module (VCM)

U2121-00: (CMU) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location Communication error with vehicle control module (VCM)
Detection condition
  • The connectivity master unit (CMU) detects a communication interruption or communication error with the vehicle control module (VCM).
Fail-safe
  • Not applicable
Possible cause
  1. Malfunction in CAN communication line between vehicle control module (VCM) and connectivity master unit (CMU)
    NOTE:
  2. Body control module (BCM) malfunction (vehicle control module (VCM) malfunction) (Refer to BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION in service information.)
  3. Connectivity master unit (CMU) malfunction (Refer to CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION in service information.)
Repeatability verification procedure
  • Not applicable
System wiring diagram
  • Not applicable