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Home >> Infiniti >> 2012 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U0101 To P0153 >> DTC P0128: Thermostat Function >> DTC Logic >> DTC Confirmation Procedure
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DTC Confirmation Procedure

  1. PRECONDITIONING
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Turn ignition switch ON.
    3. Turn ignition switch OFF and wait at least 10 seconds.

    TESTING CONDITION: 

    • For best results, perform at ambient temperature of -10°C (14°F) or higher. 
    • For best results, perform at engine coolant temperature of -10°C (14°F) to 52°C (126°F). 
    • Before performing the following procedure, do not add fuel. 

    : GO TO 2.

  2. PERFORM DTC CONFIRMATION PROCEDURE

    WITH CONSULT

    1. Turn A/C switch OFF.
    2. Turn blower fan switch OFF.
    3. Turn ignition switch ON.
    4. Select "COOLAN TEMP/S" in "DATA MONITOR" mode with CONSULT.
    5. Check the indication of "COOLAN TEMP/S".

      If it is below 52°C (126°F), go to next step.

      If it is above 52°C (126°F), cool engine down to less than 52°C (126°F). Then go to next step.

    6. Start engine and drive vehicle for 10 consecutive minutes under the following conditions.
      Vehicle speed More than 56 km/h (35 MPH)
      CAUTION: Always drive vehicle at a safe speed.
      NOTE: If "COOLAN TEMP/S" increases to more than 71 °C (160°F) within 10 minutes, turn ignition switch OFF because the test result will be OK.
    7. Check 1st trip DTC.

    WITH GST

    Follow the procedure "With CONSULT" above.

    Is 1st trip DTC detected? 

    YES: Proceed to "DIAGNOSIS PROCEDURE ".

    NO: INSPECTION END