LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2016 >> Forester 2.0XT Touring >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (Diagnostics) (H4DOTC) - Diagnostic Introduction >> Basic Diagnostic Procedure >> Procedure >> Engine
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Basic Diagnostic Procedure: Procedure: Engine

  1. CHECK ENGINE START FAILURE  .
    1. Ask the customer when and how the trouble occurred using the interview check list. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) > Check List for Interview >  CHECK   .
    2. Start the engine.

    Does the engine start?

    Yes: Go to   2  .

    No: Inspection using "Diagnostics for Engine Starting Failure". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  DIAGNOSTICS FOR ENGINE STARTING FAILURE   .

  2. CHECK ILLUMINATION OF MALFUNCTION INDICATOR LIGHT  .

    Does the malfunction indicator light illuminate?

    Yes: Go to   3  .

    No: Inspection using "General Diagnostic Table". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  GENERAL DIAGNOSTIC TABLE   .

  3. CHECK COMMUNICATION STATUS  .
    1. Turn the ignition switch to OFF.
    2. Connect the Subaru Select Monitor or general scan tool to the data link connector.
    3. Turn the ignition switch to ON, and run the Subaru Select Monitor or general scan tool.
      NOTE:
      • Subaru Select Monitor

        For detailed procedures, refer to "Subaru Select Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  SUBARU SELECT MONITOR   .

      • General scan tool

      For detailed operation procedures, refer to the general scan tool operation manual.

      Does Subaru Select Monitor communicate with vehicle normally?

    Yes: Go to   4  .

    No: Inspection using "Basic Diagnostic Procedure" of LAN system Ref. to LAN SYSTEM (DIAGNOSTICS) >  BASIC DIAGNOSTIC PROCEDURE  .

  4. CHECK DTC  .

    Read DTC using Subaru Select Monitor or general scan tool.

    NOTE:
    • Subaru Select Monitor

      Refer to "Read Diagnostic Trouble Code (DTC)" for detailed operation procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  READ DIAGNOSTIC TROUBLE CODE (DTC)   .

    • General scan tool

    For detailed operation procedures, refer to the general scan tool operation manual.

    Is DTC displayed on Subaru Select Monitor or general scan tool?

    Yes: Record DTC, time stamp, and freeze frame data, then repair the trouble cause. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  LIST OF DIAGNOSTIC TROUBLE CODE (DTC)   . After repair, go to the next step. Go to   5  .

    NOTE:
    • For the time stamp, refer to LAN article. Ref. to LAN SYSTEM (DIAGNOSTICS) > General Description >  TIME STAMP  .
    • Depending on DTCs, time stamp may not be stored.

    No: Repair the related parts.

    NOTE: If DTC is not shown on display although the malfunction indicator light illuminates, perform the diagnosis of malfunction indicator light circuit or combination meter. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  MALFUNCTION INDICATOR LIGHT   .
  5. PERFORM DIAGNOSIS  .
    1. Perform the Clear Memory Mode. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  CLEAR MEMORY MODE   .
    2. Perform the Inspection Mode or Drive Cycle. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  INSPECTION MODE   . Ref. to - ENGINE (DIAGNOSTICS) (H4DOTC) >  DRIVE CYCLE   .

    Is DTC displayed on Subaru Select Monitor or general scan tool?

    Yes: Inspect using "Diagnostic Procedure with Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC) >  DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)   .

    No: Finish the diagnosis.

scientia non olet · About LEMON Manuals