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Home >> Mazda >> 2021 >> CX-3 FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (On-Board Diagnostic - Body Control Module) >> DTC U0142-68: Communication Error With Electrical Supply Unit (ESU) >> Notes
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DTC U0142-68: Communication Error With Electrical Supply Unit (ESU): Notes

WARNING: This page is about a different car, the 2016 Mazda CX-3. However, it is still accessible from the selected car via links, so may be relevant.
Description  Communication error with electrical supply unit (ESU)
Detection condition 
  • BCM could not receive the signals from the electrical supply unit (ESU) for 5 s or more  with the ignition switched ON (engine off or on).
Fail-safe  Exterior lighting system 
  • Turn the TNS (parking lights) and headlights LO on, and turn off other exterior light controls.
Possible cause 
  • Electrical supply unit (ESU) connector or terminal malfunction
  • BCM connector or terminal malfunction
  • Short to ground in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y
  • Short to power supply in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y
  • Open circuit in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y
  • Electrical supply unit (ESU) malfunction
  • BCM malfunction
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