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Home >> Mazda >> 2021 >> 3 Select, 4D Hatchback, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> On-Board Diagnostic - Vehicle Control Module (2 Of 2) >> DTC U0401-68: Error Signal Received From Pcm, DSC HU/Cm, Instrument Cluster, Or Body Control Module (BCM) [Vehicle Control Module (Us)] >> Outline
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DTC U0401-68: Error Signal Received From Pcm, DSC HU/Cm, Instrument Cluster, Or Body Control Module (BCM) [Vehicle Control Module (Us)]: Outline

DTC U0401:68 [VEHICLE CONTROL MODULE (US)] DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location Error signal received from PCM, DSC HU/CM, instrument cluster, or body control module (BCM)
Detection condition
  • When any of the following conditions is met.
    • The vehicle control module (VCM) receives the following error signal from the PCM for 5 min.
      • Clutch stroke signal (MTx)
      • Neutral sensor signal (MTx)
      • Engine speed
      • Accelerator pedal opening angle
      • The vehicle control module (VCM) detects that the brake signals between the following modules did not match for 10 s while the brake pedal is operated.
        • PCM
        • DSC HU/CM
        • Body control module (BCM)
        • The vehicle control module (VCM) detects that a fail-safe is operated based on a deceleration request for 30 min while the vehicle is being driven.
Fail-safe (See DTC TABLE [VEHICLE CONTROL MODULE (US)] .)
Possible cause
  • PCM malfunction
    • Brake switch malfunction
    • Brake fluid pressure sensor malfunction (built into DSC HU/CM)
    • Cruise control switch malfunction
    • Neutral sensor malfunction (MTx)
    • Accelerator pedal position sensor malfunction
  • DSC HU/CM malfunction
  • Instrument cluster malfunction
  • Vehicle control module (VCM) malfunction (built into body control module (BCM))
  • Body control module (BCM) malfunction
System wiring diagram Not applicable
Connector diagram Not applicable