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Home >> Subaru >> 2017 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transaxle (Diagnostics) >> Automatic transmission system >> DTC U0100, U0122, U0140, U0155: Lost Communication With ECM/PCM "A", Lost Communication With Vehicle Dynamics, Control Module Lost Communication With Body Control Module, Lost Communication With Instrument Panel Cluster (IPC) Control Module >> Notes
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DTC U0100, U0122, U0140, U0155: Lost Communication With ECM/PCM "A", Lost Communication With Vehicle Dynamics, Control Module Lost Communication With Body Control Module, Lost Communication With Instrument Panel Cluster (IPC) Control Module: Notes

Circuit description

The transmission control computer ASSY sends/receives signals to/from ECMs via CAN communication.

NOTE:
  • Problems on the CAN bus (communication line) can be checked from the DLC3 connector. (Except when a DLC3 branch line is disconnected.)
  • Diagnostic codes related to CAN communication can be checked using SSM4.
  • Although DLC3 is connected to the CAN communication line, CAN communication cannot detect problems on the DLC3 branch lines.
DTC No. SAE/TCCS DTC detecting condition
  1. Diagnosis condition
  2. Abnormal status
  3. Abnormal period
  4. Others
 Inspection parts
U0100
  1. CAN bus is normal.
  2. Signals from ECM No CAN are lost.
  3. 500 ms, 800 ms, 2000 ms (differ depending on ID)
  4. trips
  • CAN system
U0122
  1. CAN bus is normal.
  2. Signals from skid control computer (brake actuator ASSY) are lost.
  3. 800 ms
  4. trips
  • CAN system
U0140
  1. CAN bus is normal.
  2. Signals from main body ECM (multiplex network body computer) are lost.
  3. 800 ms, 20000 ms (differ depending on ID)
  4. trips
  • CAN system
U0155
  1. CAN bus is normal.
  2. Signals from combination meter ASSY are lost.
  3. 2000 ms
  4. trips
  • CAN system
MONITOR STRATEGY DESCRIPTION

Applicable diagnostic codes U0100: Engine data not received
U0122: VDC data not received
Required sensor/component U0100: TCM
U0122: Skid control ECM
Operation frequency Consecutive
Period 1 count
MIL operation Immediate
Operation order None
TYPICAL ENABLING CONDITIONS DESCRIPTION

Battery voltage 9.0V or more
Above condition is established 1 second or more
CAN bus OFF (U0073) No defect

Inspection steps

  1. Read the diagnostic code
    1. Connect the SSM4 to the DLC3.
    2. Turn the ignition switch to ON.
    3. Read diagnostic codes according to SSM4 display. (Refer to Check list for interview )
    RESULT REFERENCE

    Result Go to
    P160A is not output at the same time. A
    P160A is output at the same time. B

    B: P160A (refer to DTC P160A RAM error )

    A: Go to Next Step.

  2. Read the diagnostic code
    1. Connect the SSM4 to the DLC3.
    2. Turn the ignition switch to ON.
    3. Read diagnostic codes according to SSM4 display. (Refer to Check list for interview )

    Next: To CAN communication system (Refer to How to troubleshoot )

Sports sequential shift switch system

Circuit description

When the shift is in M position, it can be changed to any gear using the sequential gate of the floor select lever ASSY.

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