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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 66 (Hybrid Control System - Diagnostic Codes (7 Of 7) & Circuit Tests (1 Of 2)) >> HYBRID CONTROL SYSTEM (for PHEV Model) >> DTC P31DB-9E: AC Inverter Drive Signal Stuck On [08/2023 - ] >> Procedure

DTC P31DB-9E: AC Inverter Drive Signal Stuck On [08/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 450h+ and 2024 Lexus RX 450h+. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK DTC OUTPUT (HYBRID CONTROL, PLUG-IN CONTROL) 

    Pre-procedure1

    1. None.

      Procedure1

    2. Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Powertrain > Plug-in Control > Trouble Codes 

      Result

      Result Proceed to
      P31DB-9E only is output, or DTCs except the ones in the table below are also output. A
      DTCs of hybrid control system in the tables below are output. B
      DTCs of plug-in charge control system in the tables below are output. C
      Malfunction Content System Relevant DTC
      Microcomputer malfunction Hybrid control system P0606-47 Hybrid/EV Powertrain Control Module Processor Watchdog / Safety MCU Failure
      P0606-87 Hybrid/EV Powertrain Control Module Processor to Monitoring Processor Missing Message
      P060A-29 Hybrid/EV Powertrain Control Module Monitoring Processor Signal Invalid
      P060A-44 Hybrid/EV Powertrain Control Module Monitoring Processor Data Memory Failure
      P060A-45 Hybrid/EV Powertrain Control Module Monitoring Processor Program Memory Failure
      P060A-47 Hybrid/EV Powertrain Control Module Monitoring Processor Watchdog / Safety MCU Failure
      P060A-49 Hybrid/EV Powertrain Control Module Monitoring Processor Internal Electronic Failure
      P060A-87 Hybrid/EV Powertrain Control Module Processor from Monitoring Processor Missing Message
      P060B-1C Hybrid/EV Powertrain Control Module A/D Processing Voltage Out of Range
      P060B-49 Hybrid/EV Powertrain Control Module A/D Processing Internal Electronic Failure
      P060B-71 Hybrid/EV Powertrain Control Module A/D Processing Actuator Stuck
      P1CE3-1C Hybrid/EV Powertrain Control Module Monitoring Processor A/D Processing Voltage Out of Range
      P1CE3-49 Hybrid/EV Powertrain Control Module Monitoring Processor A/D Processing Internal Electronic Failure
      P1CE3-71 Hybrid/EV Powertrain Control Module Monitoring Processor A/D Processing Actuator Stuck
      Plug-in charge control system P0606-49 Plug-in Control Module Processor Internal Electronic Failure
      Power source circuit malfunction Hybrid control system P0688-1F ECM/PCM Power Relay Sense Circuit Intermittent
      Communication system malfunction Hybrid control system U019B-87 Lost Communication with Hybrid/EV Battery Charger Control Module Missing Message
      U0293-87 Lost Communication with Hybrid/EV Powertrain Control Module Missing Message
      Sensor and actuator circuit malfunction Plug-in charge control system P1CE6-11 AC Inverter Status Signal Circuit Short to Ground
      P1CE6-15 AC Inverter Status Signal Circuit Short to Auxiliary Battery or Open
      System malfunction Plug-in charge control system P1C0F-96 AC Inverter Signal Line Component Internal Failure
      P31D9-9F AC Inverter Status Signal Stuck Off

      HINT: 

      • P31DB-9E 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.)

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    B 

    GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - 10/2024]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2024 - ] 

    Result: 

    C 

    GO TO DTC CHART (PLUG-IN CHARGE CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - ] 

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (AINM, VAIN VOLTAGE) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H58-1 (VAIN) - Body ground Ignition switch ON 3.45 to 4.05 V
      H58-2 (IND) - Body ground Ignition switch ON 4.7 to 5.5 V
      GTY1203978Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Voltage Inverter)

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - VOLTAGE INVERTER) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    Pre-procedure1

    1. Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the voltage inverter connector.
      GTY1205650Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      As DTC P1CE6-15 may be stored if the connector is disconnected when the auxiliary battery is connected, check that the the cable is disconnected from the negative (-) terminal of the auxiliary battery before performing this procedure.

    3. Disconnect the hybrid vehicle control ECU connector.
    4. Turn the ignition switch to ON.

      Procedure1

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      C59-40 (NOAC) - Body ground Ignition switch ON Below 1 V
      NOTE:

      Turning the ignition switch to ON with the hybrid vehicle control ECU connector and voltage inverter connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    6. Turn the ignition switch off.
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C59-40 (NOAC) - Body ground Ignition switch off 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    8. Reconnect the hybrid vehicle control ECU connector.
    9. Reconnect the voltage inverter connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. INSPECT VOLTAGE INVERTER 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    Pre-procedure1

    1. Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the hybrid vehicle control ECU connector.
    3. Turn the ignition switch to ON.

      Procedure1

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H58-10 (NOAC) - Body ground Ignition switch ON Below 1 V
      GTY1205002Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Voltage Inverter)
      NOTE:

      Turning the ignition switch to ON with the hybrid vehicle control ECU connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. Turn the ignition switch off.
    6. Reconnect the hybrid vehicle control ECU connector.

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE VOLTAGE INVERTER. Refer to  REMOVAL [08/2023 - ] 

  5. CHECK HARNESS AND CONNECTOR (ELECTRIC VEHICLE CHARGER ASSEMBLY - VOLTAGE INVERTER) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    Pre-procedure1

    1. Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the voltage inverter connector.
      GTY1205650Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      As DTC P1CE6-15 may be stored if the connector is disconnected when the auxiliary battery is connected, check that the the cable is disconnected from the negative (-) terminal of the auxiliary battery before performing this procedure.

    3. Disconnect the electric vehicle charger assembly connector.
    4. Turn the ignition switch to ON.

      Procedure1

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H124-56 (VAIN) - Body ground Ignition switch ON Below 1 V
      H124-60 (AINM) - Body ground Ignition switch ON Below 1 V
      NOTE:

      Turning the ignition switch to ON with the electric vehicle charger assembly connector and voltage inverter connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    6. Turn the ignition switch off.
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H124-56 (VAIN) - Body ground Ignition switch off 10 kΩ or higher
      H124-60 (AINM) - Body ground Ignition switch off 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    8. Reconnect the electric vehicle charger assembly connector.
    9. Reconnect the voltage inverter connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT ELECTRIC VEHICLE CHARGER ASSEMBLY 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    Pre-procedure1

    1. Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the voltage inverter connector.
      GTY1205650Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      As DTC P1CE6-15 may be stored if the connector is disconnected when the auxiliary battery is connected, check that the the cable is disconnected from the negative (-) terminal of the auxiliary battery before performing this procedure.

    3. Turn the ignition switch to ON.

      Procedure1

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H58-2 (IND) - Body ground Ignition switch ON 4 V or higher
      H58-1 (VAIN) - Body ground Ignition switch ON 4 V or higher
      NOTE:

      Turning the ignition switch to ON with the voltage inverter connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. Turn the ignition switch off.
    6. Reconnect the hybrid vehicle control ECU connector.

    Result: 

    OK 

    REPLACE VOLTAGE INVERTER. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    REPLACE ELECTRIC VEHICLE CHARGER ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

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