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Home >> Lexus >> 2021 >> LS 500 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (11 Of 14) >> SFI System >> DTC P16B8-71: Multi Flow Control Valve Actuator Stuck [12/2017 - ] >> Procedure

DTC P16B8-71: Multi Flow Control Valve Actuator Stuck [12/2017 - ]: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P16B8-71) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Trouble Codes.
    5. Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTC P16B8-71 is output A
      DTC P16B8-71 and other DTCs are output B

      HINT: 

      If any DTCs other than P16B8-71 are output, troubleshoot those DTCs first.

    Result: 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 09/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2018 - 09/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2019 - 10/2020]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2020 - 10/2022]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 10/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2023 - ] 

    Result: 

    See step  2

  2. CUSTOMER PROBLEM ANALYSIS AND CHECK VEHICLE (CHECK FOR OVERHEATING) 
    1. Perform a customer problem analysis to check whether overheating occurred.

      HINT: 

      Check whether "High coolant temperature warning light" was displayed on the combination meter.

      Result

      Result Proceed to
      Overheating occurred A
      Overheating did not occur B

    Result: 

    See step  7

    Result: 

    See step  3

  3. CHECK VEHICLE (CHECK FOR OVERHEATING) 
    1. Check the engine coolant quantity.

      Refer to ON-VEHICLE INSPECTION [12/2017 - ]

      Result

      Result Proceed to
      At or below reserve tank LOW level or trace of coolant boiling over A
      At or above reservoir tank LOW level and no trace of coolant boiling over B

    Result: 

    See step  7

    Result: 

    See step  4

  4. CHECK FOR COOLANT LEAK 
    1. Check the engine cooling system for coolant leaks.

      Refer to ON-VEHICLE INSPECTION [12/2017 - ]

      OK

      No leaks.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  6

    Result: 

    NG 

    See step  5

  5. REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA 
    1. Repair any engine coolant leaks.

      HINT: 

      Check for damage to parts due to overheating and replace any abnormal parts.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. ADD COOLANT 
    1. Fill the reservoir tank up to the FULL line with engine coolant.

      Refer to REPLACEMENT [12/2017 - ]

      HINT: 

      Add engine coolant and perform air bleeding after repair.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    5. Turn the engine switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE MULTI FLOW CONTROL VALVE POSITION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Active Test / Control the Multi Flow Control Valve Position / Data List / Actual Multi Flow Control Valve Position.

      Powertrain > Engine > Active Test 

      Active Test Display
      Control the Multi Flow Control Valve Position
      Data List Display
      Actual Multi Flow Control Valve Position
    5. Read the Data List when the water control valve is operated.

      OK

      The value of the Data List item "Actual Multi Flow Control Valve Position" follows the command value and changes smoothly when the Active Test is operated in all ranges.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  9

  9. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

    5. Turn the engine switch off and wait for at least 30 seconds.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  10

  10. CHECK WHETHER DTC OUTPUT RECURS (DTC P16B8-71) 
    1. Start the engine.
    2. Idle the engine for 120 seconds or more.
    3. Turn the engine switch off and wait for at least 30 seconds.
    4. Start the engine from a cold condition.
    5. Drive the vehicle on urban roads until the Data List item "Coolant Temperature Controlling Value" rises to 60°C (140°F) or higher.
    6. Turn the air conditioning on (max cool).
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      Powertrain > Engine > Utility 

      Tester Display
      All Readiness
    9. Input the DTC: P16B8-71.
    10. Check the DTC judgment result.

      Result

      Result Proceed to
      NORMAL
      (DTCs are not output)
      A
      ABNORMAL
      (DTC P16B8-71 is output)
      B

    Result: 

    REPLACE ENGINE COOLANT 

    Refer to REPLACEMENT [12/2017 - ]

    HINT: 

    Even when no DTC is output, replace the coolant because foreign matter trapped in the coolant may cause temporary locking.

    Result: 

    See step  12

  11. INSPECT ECM (INTERNAL CIRCUIT) 
    GTY825095Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to Water Control Valve)
    *b Waveform of FCM+ terminal and FCM- terminal during fail-safe
    1. Disconnect the water control valve connector.
    2. Inspect the ECM using an oscilloscope.
    3. Turn the engine switch on (IG).
    4. Connect an oscilloscope between the terminals of the water control valve.
      ECM Terminal Name D39-4 (FCM+) - D39-5 (FCM-)
      Tester Range 2 V/DIV., 1 ms./DIV.
      Condition Engine switch on (IG)
    5. While the engine switch is on (IG), check the waveform between the FCM+ terminal and FCM- terminal during fail-safe.

      Standard

      25% duty waveform is output

      HINT: 

      • Check the operation circuit of the ECM by checking the waveform during fail-safe.
      • Because fail-safe is prohibited when the ambient temperature is 0°C (32°F) or less, work in a location where the ambient temperature is 5°C (41°F) or higher.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the Techstream.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  12

  12. REPLACE WATER CONTROL VALVE 
    1. Replace the water control valve.

      Refer to REMOVAL [12/2017 - 09/2018] , or refer to REMOVAL [09/2018 - 10/2020] , or refer to REMOVAL [10/2020 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    REPLACE ENGINE COOLANT. Refer to  REPLACEMENT [12/2017 - ] 

  13. CHECK HARNESS AND CONNECTOR (WATER CONTROL VALVE - ECM) 
    1. Disconnect the water control valve connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-4 (FCM+) - D2-15 (FCM+) Always Below 1 Ω
      D39-5 (FCM-) - D2-16 (FCM-) Always Below 1 Ω
      D39-4 (FCM+) or D2-15 (FCM+) - Body ground and other terminals Always 10 kΩ or higher
      D39-5 (FCM-) or D2-16 (FCM-) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023]  , or refer to  REMOVAL [10/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR