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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Exhaust Heat RECIRCULATION System (A25A-FXS) - Diagnostics & Circuit Tests) >> Exhaust Heat RECIRCULATION System >> Exhaust Heat Recirculation System Circuit [12/2019 - ] >> Procedure

Exhaust Heat Recirculation System Circuit [12/2019 - ]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - TEMPERATURE SWITCH (FOR EXHAUST HEAT RECIRCULATION SYSTEM) - BODY GROUND) 
    1. Disconnect the Q2 temperature switch (for exhaust heat recirculation system) connector.
    2. Disconnect the H21 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Q2-2 (TWS2) - H21-38 (TWS2) Always Below 1 Ω
      Q2-1 (GND) - Body ground Always Below 1 Ω
      Q2-2 (TWS2) or H21-38 (TWS2) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (TEMPERATURE SWITCH (FOR EXHAUST HEAT RECIRCULATION SYSTEM) - COMBINATION METER ASSEMBLY) 

    Result: 

    OK 

    See step  2

  2. CHECK COMBINATION METER ASSEMBLY 
    1. Turn the ignition switch to ON.
    2. Disconnect the Q2 temperature switch (for exhaust heat recirculation system) connector.
    3. Check the water temperature receiver gauge in the combination meter assembly.

      Result

      Result Proceed to
      Water temperature receiver gauge needle jumps from normal value to HI side A
      Water temperature receiver gauge needle jumps to HI side and stays there even after the connector is disconnected B
      Water temperature receiver gauge needle does not move from normal value even after the connector is disconnected C

    Result: 

    A 

    END 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    B 

    See step  3

  3. REPLACE TEMPERATURE SWITCH (FOR EXHAUST HEAT RECIRCULATION SYSTEM) 
    1. Replace the temperature switch (for exhaust heat recirculation system).

      Refer to REMOVAL [12/2019 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  4. CHECK COMBINATION METER ASSEMBLY 
    1. Turn the ignition switch to ON.
    2. Disconnect the Q2 temperature switch (for exhaust heat recirculation system) connector.
    3. Check the water temperature receiver gauge in the combination meter assembly.

      Result

      Result Proceed to
      Water temperature receiver gauge needle jumps from normal value to HI side A
      Water temperature receiver gauge needle jumps to HI side and stays there even after the connector is disconnected B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

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