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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (Hybrid Control System (Diagnostic Codes) (3 Of 5)) >> Hybrid Control System >> DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [10/2018 - ] >> Procedure

DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [10/2018 - ]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus UX 250h, 2023 Lexus UX 250h, 2022 Lexus UX 250h, 2021 Lexus UX 250h, and 2020 Lexus UX 250h. However, it is still accessible from the selected car via links, so may be relevant.
  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
      P0C7396 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 P060647 Hybrid/EV Powertrain Control Module Processor Watchdog / Safety MCU Failure
      P06881F ECM/PCM Power Relay Sense Circuit Intermittent
      Sensor and actuator circuit malfunction P314A31 Motor Electronics Coolant Pump "A" No Signal

      HINT: 

      P0C7396 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 [10/2018 - ] 

    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 / Hybrid Control / Data List / Inverter Water Pump Revolution.
    4. According to the display on the Techstream, read the Data List.

      Powertrain > Hybrid Control > Data List 

      Tester Display
      Inverter Water Pump Revolution

      Result

      Tester Display Switch 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 lower than 200 rpm.

    5. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    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 Switch Condition Specified Condition
      Inverter Water Pump Revolution Power switch on (IG) 3176 to 8617 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 lower than 200 rpm.
    6. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    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: 

    A 

    See step  12

    Result: 

    B 

    REPLACE HV COOLANT. Refer to  REPLACEMENT [10/2018 - ] 

  6. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) 

    Refer to PROCEDURE - Step 1

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  7

  7. 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 [10/2018 - ]

      GTY779463Courtesy 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  8

  8. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A46 hybrid vehicle control ECU connector.
    2. Disconnect the A3 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 Switch Condition Specified Condition
      A46-34 (IWP) - A3-3 (SWP) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Switch Condition Specified Condition
      A46-34 (IWP) or A3-3 (SWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      GTY807170Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)
      *b Front view of wire harness connector
      (to Inverter Water Pump Assembly)

      HINT: 

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

    4. Reconnect the A3 inverter water pump assembly connector.
    5. Reconnect the A46 hybrid vehicle control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. 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.
      GTY784099Courtesy 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 / Hybrid Control / Data List / Inverter Water Pump Revolution.
    5. According to the display on the Techstream, read the Data List.

      Powertrain > Hybrid Control > Data List 

      Tester Display
      Inverter Water Pump Revolution

      Result

      Tester Display Switch 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. Refer to  REMOVAL [10/2018 - 07/2022]  Refer to  REMOVAL [07/2022 - ] 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A46 hybrid vehicle control ECU 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.
      GTY796487Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block
      *2 INV W/PMP Relay

      HINT: 

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

    4. Measure the voltage according to the value(s) in the table below.
      GTY800458Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 *b Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A46-34 (IWP) - F59-3 (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 A46 hybrid vehicle control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  11

  11. CHECK HYBRID VEHICLE CONTROL ECU (CHECK WAVEFORM) 
    1. Connect an oscilloscope between the hybrid vehicle control ECU terminals specified in the table below.
    2. Check the waveform while turning the power switch on (IG).
      GTY780621Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -
      Item Content
      Terminal A46-34 (IWP) - F59-3 (E1)
      Equipment Setting 5 V/DIV., 50 ms./DIV.
      Condition Power switch on (IG)

      OK

      Waveform duty ratio is between 3% and 9%.

    3. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  12

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [10/2018 - 07/2022]  Refer to  REMOVAL [07/2022 - ] 

  12. REPLACE INVERTER WATER PUMP ASSEMBLY 

    Refer to REMOVAL [10/2018 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  13

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

      Refer to PROCEDURE - Step 3

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

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