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Home >> Toyota >> 2018 >> Prius One >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Control System (Nickel Metal Hydride) - Diagnostic Codes (4 Of 9) >> HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY) >> DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [11/2015 -] >> Procedure

DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure [11/2015 -]: 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 [11/2015 - 11/2017]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2017 - 12/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2018 - 08/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2019 - 06/2021]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [06/2021 -] 

    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 12 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.

      Powertrain > Hybrid Control > Data List 

      Tester Display
      Inverter Water Pump Revolution
    4. According to the display on the Techstream, read the Data List.

      HINT: 

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

      Result

      Result Proceed to
      The value of Inverter Water Pump Revolution is 200 rpm or less A
      Other than above B
    5. Turn the power switch off.

    Result: 

    B 

    See step  6

    Result: 

    A 

    See step  3

  3. CLEAR DTC 
    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. Clear the DTCs and freeze frame data.

      Powertrain > Hybrid Control > Clear DTCs 

    5. Turn the power switch off and wait for 2 minutes or more.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  4. PERFORM ACTIVE TEST 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 12 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
      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".

      OK

      Tester Display Condition Specified Condition
      Inverter Water Pump Revolution Power switch on (IG)
      During Active Test      		 3000 to 9300 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) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Read the freeze frame data item Ambient Temperature using the Techstream.

      Powertrain > Hybrid Control > DTC (P0C73-96) > Freeze Frame Data 

      Tester Display
      Ambient Temperature
    4. Check if the freeze frame data item Ambient Temperature is below the freezing temperature of the HV coolant.

      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

      HINT: 

      • HV coolant (SLLC) with a 30% concentration freezes at -15°C (5°F) and HV coolant (SLLC) with a 50% concentration freezes at -35°C (-31°F).
      • If the HV coolant freezes in the HV radiator or inverter water pump, the coolant temperature in the inverter with converter assembly rises because the HV coolant cannot circulate. As a result, a DTC may be stored.
      • A DTC is stored when the inverter water pump impeller cannot rotate due to freezing of the HV coolant.
      • If DTCs are output due to freezing of the LLC, the problem symptom cannot be reproduced. Check the LLC replacement history and whether the LLC was frozen based on the ambient temperature when the DTCs were stored.
    5. Turn the power switch off.

    Result: 

    A 

    See step  12

    Result: 

    B 

    REPLACE HV COOLANT. Refer to  REPLACEMENT [11/2015 -] 

  6. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) 
    1. Check the connector connections and contact pressure of the relevant terminals for the hybrid vehicle control ECU connectors.

      HINT: 

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2015 -]

      GTY542745Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      The connectors are connected securely and there are no contact pressure problems.

      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.

      HINT: 

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2015 -]

      GTY542781Courtesy 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 A50 hybrid vehicle control ECU connector.
    2. Disconnect the A7 inverter water pump assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      (A50, A7)

      (A50)

      (A7)

      Tester Connection Condition Specified Condition
      A50-34 (IWP) - A7-3 (SWP) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      (A50, A7)

      (A50)

      (A7)

      Tester Connection Condition Specified Condition
      A50-34 (IWP) or A7-3 (SWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      GTY561487Courtesy 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: 

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

    4. Reconnect the A7 inverter water pump assembly connector.
    5. Reconnect the A50 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 12 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 and No. 1 junction block assembly.
      GTY540924Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *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.

      Powertrain > Hybrid Control > Data List 

      Tester Display
      Inverter Water Pump Revolution
    5. According to the display on the Techstream, read the Data List.

      Result

      Result Proceed to
      The value of Inverter Water Pump Revolution is 200 rpm or less A
      Other than above B
    6. Turn the power switch off.
    7. Install the INV W/PMP fuse.

    Result: 

    B 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 08/2019]  , or refer to  REMOVAL [08/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 -] 

    Result: 

    A 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A50 hybrid vehicle control ECU connector.
    2. Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Connect terminals 3 and 5 of the IGCT relay holder.
      GTY541585Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 IGCT 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.
      GTY604271Courtesy 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

      (A50, F3)

      (A50)

      (F3)

      Tester Connection Condition Specified Condition
      A50-34 (IWP) - F3-3 (E1) IGCT 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 IGCT relay.
    6. Reconnect the A50 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. Turn the power switch on (IG).
    3. While turning the power switch on (IG), check the waveform between the hybrid vehicle control ECU terminals.
      GTY540223Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -
      Item Content
      Terminal A50-34 (IWP) - F3-3 (E1)
      Equipment Setting 5 V/DIV., 50 ms./DIV.
      Condition Power switch on (IG)

      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. Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 08/2019]  , or refer to  REMOVAL [08/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 -] 

    Result: 

    OK 

    See step  12

  12. REPLACE INVERTER WATER PUMP ASSEMBLY 

    HINT: 

    Refer to REMOVAL [11/2015 -]

    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.

      HINT: 

      Refer to REPLACEMENT [11/2015 -]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

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