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Home >> Toyota >> 2022 >> Avalon XLE >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Hybrid Control System (Nickel Metal Hydride) - Diagnostic Codes (P314A-U0424) & Circuit Tests) >> HYBRID CONTROL SYSTEM (for NICKEL METAL HYDRIDE BATTERY) >> DTC P314A-31: Motor Electronics Coolant Pump "A" No Signal [04/2018 - 08/2020] >> Procedure

DTC P314A-31: Motor Electronics Coolant Pump "A" No Signal [04/2018 - 08/2020]: Procedure

WARNING: This page is about a different car, the 2020 Toyota Avalon and 2019 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. CLEAR DTC 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  2

  2. 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.
    • 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/Active Test/Activate the Inverter Water Pump.
    4. Perform the "Activate the Inverter Water Pump" Active Test.

      Powertrain > Hybrid Control > Active Test 

      Tester Display
      Activate the Inverter Water Pump
    5. Touch the inverter water pump assembly and check that it is operating (vibrating).

      OK

      The inverter water pump is operating (vibrating).

      HINT: 

      Perform the Active Test with the inverter coolant temperature between -15 and 65°C (5 to 149°F).

    6. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  3

  3. 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  4

  4. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR) 

    Refer to PROCEDURE - Step 7

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INVERTER WATER PUMP ASSEMBLY) 
    1. Disconnect the A23 hybrid vehicle control ECU connector.
    2. Disconnect the X1 inverter water pump assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY898224Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear view of wire harness connector
      (to Hybrid Vehicle Control ECU)
      *b Front view of wire harness connector
      (to Inverter Water Pump Assembly)

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      A23-14 (NIWP) - X1-2 (NWP) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      A23-14 (NIWP) or X1-2 (NWP) -Body ground and other terminals Power switch off 10 kΩ or higher
    4. Reconnect the X1 inverter water pump assembly connector.
    5. Reconnect the A23 hybrid vehicle control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HYBRID VEHICLE CONTROL ECU 
    1. Disconnect the X1 inverter water pump assembly connector.
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A23-14 (NIWP) - G46-6 (E1) Power switch on (IG) 11 to 14 V
      GTY856489Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)
    4. Turn the power switch off.
    5. Reconnect the X1 inverter water pump assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [04/2018 - 08/2021] 

    Result: 

    OK 

    See step  7

  7. CLEAR DTC 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  8

  8. PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE INVERTER WATER PUMP) 
    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. Turn the power switch on (IG).
    3. Enter the following menus: Powertrain/Hybrid Control/Active Test/Activate the Inverter Water Pump.
    4. Perform the "Activate the Inverter Water Pump" Active Test.

      Powertrain > Hybrid Control > Active Test 

      Tester Display
      Activate the Inverter Water Pump
    5. Connect an oscilloscope between the hybrid vehicle control ECU terminals specified in the table below, and measure the waveform.
      Item Content
      Terminal A23-14 (NIWP) - G46-6 (E1)
      Equipment Setting 5 V/DIV., 5 ms./DIV.
      Condition Power switch on (IG), during Active Test

      OK

      The period of the wavelength is 13 msec or less.

      GTY915010Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)
    6. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [04/2018 - 08/2021] 

    Result: 

    NG 

    See step  12

  9. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR) 

    Refer to PROCEDURE - Step 7

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - IGCT RELAY) 
    1. Remove the IGCT relay from the No. 3 relay block.
    2. Disconnect the X1 inverter water pump assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY939310Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 3 Relay Block *2 IGCT Relay Holder
      *a Front view of wire harness connector
      (to Inverter Water Pump Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      X1-4 (+BWP) - 5 (IGCT relay holder) Power switch off Below 1 Ω
      NOTE:

      Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

      HINT: 

      • Connectors

        Slightly shake the connector vertically and horizontally.

      • Wire Harness

        Slightly shake the wire harness vertically and horizontally.

        The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly.

      • No. 3 Relay Block

        Apply slight vibration with a finger to the No. 3 relay block and check whether a malfunction occurs.

      • INV W/PMP fuse

        Apply slight vibration with a finger to the INV W/PMP fuse and check whether a malfunction occurs.

      • IGCT relay

        Apply slight vibration with a finger to the IGCT relay and check whether a malfunction occurs.

      GTY443038Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Example
      *b Shake Slightly
      *c Vibrate Slightly
    4. Reconnect the X1 inverter water pump assembly connector.
    5. Install the IGCT relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - BODY GROUND) 
    1. Disconnect the X1 inverter water pump assembly connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY869778Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Inverter Water Pump Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      X1-1 (GND) - Body ground Power switch off Below 1 Ω
    3. Reconnect the X1 inverter water pump assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. REPLACE INVERTER WATER PUMP ASSEMBLY 

    Refer to REMOVAL [04/2018 - ]

    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 REPLACEMENT [04/2018 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  14. CHECK FUSE (INV W/PMP) 
    1. Remove the INV W/PMP fuse from the No. 4 relay block.
      GTY744268Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block
      *2 INV W/PMP Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      INV W/PMP fuse Always Below 1 Ω
    3. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CONNECT SECURELY (INVERTER WATER PUMP ASSEMBLY CONNECTOR) 

    Result: 

    NG 

    See step  18

  15. CHECK INSTALLATION CONDITION (INV W/PMP FUSE) 
    1. Check installation condition of the INV W/PMP fuse.

      OK

      INV W/PMP fuse is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  19

    Result: 

    OK 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY CIRCUIT) 
    1. Remove the INV W/PMP fuse from No. 4 relay block.
    2. Remove the IGCT relay from the No. 3 relay block.
    3. Disconnect the X1 inverter water pump assembly connector.
    4. Measure the resistance according to the value(s) in the table below.
      GTY940939Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 3 Relay Block *2 IGCT Relay Holder
      *3 No. 4 Relay Block *4 INV W/PMP Fuse Holder
      *a Front view of wire harness connector
      (to Inverter Water Pump Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (INV W/PMP fuse holder) - X1-4 (+BWP) Power switch off Below 1 Ω
      1 (INV W/PMP fuse holder) - 5 (IGCT relay holder) Power switch off Below 1 Ω
      2 (INV W/PMP fuse holder) or X1-4 (+BWP) - Body ground and other terminals Power switch off 10 kΩ or higher
      NOTE:

      Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

    5. Reconnect the X1 inverter water pump assembly connector.
    6. Install the IGCT relay.
    7. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  21

    Result: 

    OK 

    See step  17

  17. CHECK FUSE (INV W/PMP) 
    1. Remove the INV W/PMP fuse from the No. 4 relay block.
      GTY769363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block
      *2 INV W/PMP Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      INV W/PMP fuse Always Below 1 Ω
    3. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP FUSE HOLDER TERMINAL) 

    Result: 

    NG 

    See step  22

  18. CONNECT SECURELY 
    1. Connect the inverter water pump assembly connector securely.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    REPLACE FUSE (INV W/PMP) 

  19. CHECK FUSE HOLDER TERMINAL (INV W/PMP FUSE) 
    1. Check the terminals of the INV W/PMP fuse holder.

      OK

      The terminals of the INV W/PMP fuse holder are not bent, loose or corroded.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  26

    Result: 

    OK 

    See step  20

  20. CHECK FUSE (INV W/PMP) 
    1. Remove the INV W/PMP fuse from the No. 4 relay block.
      GTY769363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block
      *2 INV W/PMP Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      INV W/PMP fuse Always Below 1 Ω
    3. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CONNECT SECURELY (INV W/PMP FUSE) 

    Result: 

    NG 

    REPLACE FUSE (INV W/PMP) 

  21. CHECK FUSE (INV W/PMP) 
    1. Remove the INV W/PMP fuse from the No. 4 relay block.
      GTY769363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block
      *2 INV W/PMP Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      INV W/PMP fuse Always Below 1 Ω
    3. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    See step  27

  22. CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - BODY GROUND) 
    1. Disconnect the X1 inverter water pump assembly connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY933137Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Inverter Water Pump Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      X1-1 (GND) - Body ground Power switch off Below 1 Ω
    3. Reconnect the X1 inverter water pump assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  27

    Result: 

    OK 

    See step  23

  23. CHECK FUSE HOLDER TERMINAL (INV W/PMP FUSE) 
    1. Check the terminals of the INV W/PMP fuse holder.

      OK

      The terminals of the INV W/PMP fuse holder are not bent, loose or corroded.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  28

    Result: 

    OK 

    See step  24

  24. REPLACE INVERTER WATER PUMP ASSEMBLY 

    Refer to REMOVAL [04/2018 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  25

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

      Refer to REPLACEMENT [04/2018 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    REPLACE FUSE (INV W/PMP) 

  26. CHECK FUSE (INV W/PMP) 
    1. Remove the INV W/PMP fuse from the No. 4 relay block.
      GTY769363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 relay block
      *2 INV W/PMP Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      INV W/PMP fuse Always Below 1 Ω
    3. Install the INV W/PMP fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP FUSE HOLDER TERMINAL) 

    Result: 

    NG 

    See step  28

  27. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (INV W/PMP) 

  28. REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP FUSE HOLDER TERMINAL) 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (INV W/PMP) 

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