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Home >> Mazda >> 2021 >> 3 Select, 4D Hatchback, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Collision/Avoidance >> On-Board Diagnostic - Vehicle Control Module (2 Of 2) >> DTC U0121-00: Communication Error With DSC HU/Cm [Vehicle Control Module (Us)] >> Outline
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DTC U0121-00: Communication Error With DSC HU/Cm [Vehicle Control Module (Us)]: Outline

DTC U0121:00 [VEHICLE CONTROL MODULE (US)] DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location Communication error with DSC HU/CM
Detection condition
  • The vehicle control module (VCM) cannot receive CAN signal from DSC HU/CM for 10 s.
Fail-safe (See DTC TABLE [VEHICLE CONTROL MODULE (US)] .)
Possible cause
  • Malfunction in CAN communication line between vehicle control module (VCM) and DSC HU/CM
  • DSC HU/CM malfunction
  • Vehicle control module (VCM) malfunction (built into body control module (BCM))
System wiring diagram Not applicable