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Inspection Mode 10

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.
DTC Description & trouble part Note
U1678 LIN COMMUNICATION BUS 4 ERROR BODY CONTROL MODULE BIU detects DTC only when [Light LIN setting] is [Support].
U1781 LOST COMMUNICATION WITH LDM RH MODULE BIU detects DTC only when [Light LIN setting] is [Support].
U178A LOST COMMUNICATION WITH LDM LH MODULE BIU detects DTC only when [Light LIN setting] is [Support].

Diagnostic procedure: 

  1. Using the Subaru Select Monitor, perform the clear memory of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY
  2. Using the Subaru Select Monitor, read the DTC of [Body Control] to check that there is no DTC displayed. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 
    NOTE:

    If the DTC is displayed on the screen, the trouble is still present. Perform the diagnosis for the displayed DTCs. After solving the DTC, repeat from step   1 . 

  3. After the ignition switch is turned ON, wait for 5 seconds or more.
  4. Repeat the step  3 three or more times.
  5. Using the Subaru Select Monitor, read the DTC of [Body Control] to check that there is no DTC displayed. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 
    NOTE:

    If the DTC is displayed on the screen, the trouble is still present. Perform the diagnosis for the displayed DTCs.