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Home >> Lexus >> 2022 >> LS 500h RWD >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Control System (W/ Advanced Park) - Diagnostic Codes (3 Of 5) >> HYBRID CONTROL SYSTEM (w/ Advanced Park) >> DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [11/2021 - 10/2023] >> Procedure

DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [11/2021 - 10/2023]: Procedure

  1. CHECK DTC OUTPUT (HYBRID CONTROL) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.
    4. Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Result

      Result Proceed to
      P0C73-96 only is output, or DTCs except the ones in the table below are also output. A
      Any of the following DTCs including pending DTCs are also output. B
      Malfunction Content Relevant DTC
      Microcomputer malfunction P0606-47 Hybrid/EV Powertrain Control Module Processor Watchdog / Safety MCU Failure
      P0688-1F ECM/PCM Power Relay Sense Circuit Intermittent
      Sensor and actuator circuit malfunction P314A-31 Motor Electronics Coolant Pump "A" No Signal

      HINT: 

      P0C73-96 may be output as a result of the malfunction indicated by the DTCs above.

      1. The chart above is listed in inspection order of priority.
      2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)
    5. Turn the power switch off.

    Result: 

    B 

    GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - 10/2023] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (INVERTER WATER PUMP REVOLUTION) 
    NOTE:

    Be sure to perform the inspection with the auxiliary battery voltage at 11 V or more.

    HINT: 

    • When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.
    • When the inverter water pump assembly signal line (SWP - IWP) is open or its connection is faulty, the inverter water pump assembly is operated forcibly.
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Enter the following menus: Powertrain / Motor Generator Control / Data List / Inverter Water Pump Revolution.
    4. According to the display on the Techstream, read the Data List.

      Powertrain > Motor Generator > Data List 

      Tester Display
      Inverter Water Pump Revolution

      Result

      Tester Display Condition Specified Condition
      Inverter Water Pump Revolution Power switch on (IG) 200 rpm or less

      HINT: 

      When the inverter water pump assembly is not operating, the Data List item "Inverter W/P Revolution" displays a value 200 rpm or less.

    5. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  3

  3. CLEAR DTC 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  4

  4. READ VALUE USING TECHSTREAM (ACTIVATE THE INVERTER WATER PUMP) 
    NOTE:
    • Make sure that the HV coolant level is above the low line of the inverter reserve tank.
    • Be sure to perform the inspection with the auxiliary battery voltage at 11 V or more.

    HINT: 

    When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.

    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Enter the following menus: Powertrain / Hybrid Control / Active Test / Activate the Inverter Water Pump.
    4. Select the Data List item "Inverter Water Pump Revolution".

      Powertrain > Hybrid Control > Active Test 

      Active Test Display
      Activate the Inverter Water Pump
      Data List Display
      Inverter Water Pump Revolution
    5. According to the display on the Techstream, perform the Active Test "Activate the Inverter Water Pump" and, check the value of the Data List item "Inverter Water Pump Revolution".

      Result

      Tester Display Condition Specified Condition
      Inverter Water Pump Revolution Power switch on (IG) 3200 to 8600 rpm

      HINT: 

      • Perform the Active Test with the inverter coolant temperature between -15 and 65°C (5 to 149°F).
      • When the inverter water pump assembly is not operating, the Data List item "Inverter Water Pump Revolution" displays a value 200 rpm or less.
    6. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  5

  5. CHECK HV COOLANT (CHECK FOR CONDITIONS THAT MAY HAVE CAUSED FREEZING) 

    Refer to PROCEDURE - Step 7

    Result

    Result Proceed to
    Ambient Temperature value is above freezing temperature of the HV coolant. A
    Ambient Temperature value is below freezing temperature of the HV coolant. B

    Result: 

    B 

    REPLACE HV COOLANT. Refer to  REPLACEMENT [10/2017 - 10/2023] 

    Result: 

    A 

    See step  6

  6. REPLACE INVERTER WATER PUMP ASSEMBLY 
    1. Replace inverter water pump assembly.

      Refer to REMOVAL [10/2017 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  7

  7. ADD HV COOLANT AND PERFORM AIR BLEEDING 
    1. After replacing the inverter water pump assembly, add HV coolant and perform air bleeding.

      Refer to REPLACEMENT [10/2017 - 10/2023]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  8. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU ASSEMBLY CONNECTOR) 

    Refer to PROCEDURE - Step 1

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  9

  9. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR) 
    1. Check the connector connections and contact pressure of the relevant terminals for the inverter water pump assembly connector.

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [10/2017 - ]

      GTY794227Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      The connector is connected securely, the terminals are not deformed or corroded and there are no contact problems.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A107 hybrid vehicle control ECU assembly connector.
    2. Disconnect the A84 inverter water pump assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      A107-31 (IWP) - A84-3 (SWP) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      A107-31 (IWP) or A84-3 (SWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      GTY1086314Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU Assembly)
      *b Front view of wire harness connector
      (to Inverter Water Pump Assembly)

      HINT: 

      Check the condition (looseness, deterioration, etc.) of the wire to body ground for the inverter water pump assembly.

    4. Reconnect the A84 inverter water pump assembly connector.
    5. Reconnect the A107 hybrid vehicle control ECU assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. READ VALUE USING TECHSTREAM (INVERTER WATER PUMP REVOLUTION) 
    NOTE:

    Be sure to perform the inspection with the auxiliary battery voltage at 11 V or more.

    HINT: 

    When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.

    1. Connect the Techstream to the DLC3.
    2. Remove the INV W/PMP fuse from No. 1 engine room relay block.
      GTY811517Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block
      *2 INV W/PMP Fuse
    3. Turn the power switch on (IG).
    4. Enter the following menus: Powertrain / Motor Generator Control / Data List / Inverter Water Pump Revolution.
    5. According to the display on the Techstream, read the Data List.

      Powertrain > Motor Generator > Data List 

      Tester Display
      Inverter Water Pump Revolution

      Result

      Tester Display Condition Specified Condition
      Inverter Water Pump Revolution Power switch on (IG) 200 rpm or less
    6. Turn the power switch off.
    7. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A107 hybrid vehicle control ECU assembly connector.
    2. Remove the INV W/PMP relay from the No. 1 engine room relay block.
    3. Connect terminals 3 and 5 of the INV W/PMP relay holder.

      HINT: 

      Make a short circuit between terminals 3 and 5 to supply +B voltage to the inverter water pump.

      GTY805014Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block
      *2 INV W/PMP Relay
    4. Measure the voltage according to the value(s) in the table below.
      GTY1084895Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU Assembly)      		 *b Rear view of wire harness connector
      (to Hybrid Vehicle Control ECU Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A107-31 (IWP) - G166-15 (E1) INV W/PMP relay holder terminals 3 and 5 connected
      Power switch off      		 11 to 14 V
      NOTE:

      Make sure to check for and clear DTCs after performing this inspection.

    5. Install the INV W/PMP relay.
    6. Reconnect the A107 hybrid vehicle control ECU assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  16

    Result: 

    OK 

    See step  13

  13. CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY (CHECK WAVEFORM) 
    1. Connect an oscilloscope between the hybrid vehicle control ECU assembly terminals specified in the table below.
    2. Turn the power switch on (IG).
    3. While turning the power switch on (IG), check the waveform between the hybrid vehicle control ECU assembly terminals.
      GTY1084672Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU Assembly)      		 - -
      Tester Connection Condition Equipment Setting
      A107-31 (IWP) - G166-15 (E1) Power switch on (IG) 5 V/DIV., 50 ms./DIV.

      OK

      Waveform duty ratio is between 3% and 9%.

    4. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    OK 

    See step  14

  14. REPLACE INVERTER WATER PUMP ASSEMBLY 
    1. Replace inverter water pump assembly.

      Refer to REMOVAL [10/2017 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  15

  15. ADD HV COOLANT AND PERFORM AIR BLEEDING 
    1. After replacing the inverter water pump assembly, add HV coolant and perform air bleeding.

      Refer to REPLACEMENT [10/2017 - 10/2023]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  16. REPLACE INVERTER WATER PUMP ASSEMBLY 
    1. Replace inverter water pump assembly.

      Refer to REMOVAL [10/2017 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  17

  17. ADD HV COOLANT AND PERFORM AIR BLEEDING 
    1. After replacing the inverter water pump assembly, add HV coolant and perform air bleeding.

      Refer to REPLACEMENT [10/2017 - 10/2023]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

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