LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 2024 >> CX-90 Turbo Select >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 8 (On-Board Diagnostic - Pcm (VIN A) (4 Of 4)) >> DTC U04C0-00: Backup Power Supply Unit System: Internal Malfunction (PYUL)

DTC U04C0-00: Backup Power Supply Unit System: Internal Malfunction (PYUL)

WARNING: This page is about a different variant/trim than selected.
U04C0: 00 (PCM (PYUL)) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location Backup power supply unit system: Internal malfunction
Detection condition
  • The following conditions are met:
    • The backup power supply unit detects an internal malfunction.
    • The PCM normally receives malfunction information from the backup power supply unit.
Precondition 
  • Switch the ignition ON (engine off or on)
Fail-safe
  • Inhibits auto door lock operation. (with auto door lock system)
  • Displays/turns on shift system warning indication/warning light.
  • Inhibits engine-stop by i-stop control.
Possible cause
  1. Backup power supply unit malfunction (Refer to [BACKUP POWER SUPPLY UNIT REMOVAL/INSTALLATION ] ).
  2. PCM malfunction (Refer to [PCM REMOVAL/INSTALLATION ] ).
Repeatability verification procedure
  1. Clear the DTC recorded in the memory. (See CLEARING DTC .)
  2. Replicate the vehicle conditions at the time the DTC was detected using the following procedure.
    WARNING:
    • Observe legal speed limits when driving the vehicle and perform the procedure in a location where safety can be assured.
    • To prevent an accident, work with two people when the vehicle is being driven (one person drives vehicle, other person operates M-MDS).
    • Try to reproduce the malfunction by driving the vehicle based on the values in the freeze frame data/snapshot data.
System Wiring Diagram
  • Not applicable