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Home >> Subaru >> 2017 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (3 Of 3) >> EFI system (FA20) >> DTC U0073 Control Module Communication Bus "A" Off; DTC U0101 Lost Communication With TCM; DTC U0122 Lost Communication With Vehicle Dynamics Control Module; DTC U0155 Lost Communication With Instrument Panel Cluster (IPC) Control Module; DTC U0402 Invalid Data Received From TCM; DTC U0416 Invalid Data Received From Vehicle Dynamics Control Module; DTC U0423 Invalid Data Received From Instrument Panel Cluster Control Module >> Circuit description >> Notes
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Circuit description: Notes

The engine control computer, the transmission control computer, the skid control computer (brake actuator ASSY), and the combination meter ASSY send and receive data via CAN communication line. When a communication error occurs between each computer, the engine control computer outputs the DTCs.

DTC No. DTC detection conditions Faulty part
U0073 Bus OFF status continues for 0.436 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
U0101 Communication between ECM and TCM becomes impossible for 0.5 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • TCM
U0122 Communication between ECM and skid control ECM becomes impossible for 0.5 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • Brake actuator ASSY
U0155 Communication between ECM and combination meter ASSY becomes impossible for 0.5 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • Combination meter ASSY
U0402 Invalid data has been received from TCM for 2 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • TCM
U0416 Invalid data has been received from skid control ECM for 2 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • Brake actuator ASSY
U0423 Invalid data has been received from combination meter ASSY for 2 seconds or more. (1 trips detection logic)
  • Wiring harness (CANL - CANH circuit)
  • ECM
  • Combination meter ASSY