LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 23 (Hybrid Control System - Diagnostic Codes (1 Of 7)) >> HYBRID CONTROL SYSTEM (for PHEV Model) >> DTC P0A08-14: DC/DC Converter Status Circuit Short to Ground or Open [08/2023 - ] >> Procedure

DTC P0A08-14: DC/DC Converter Status Circuit Short to Ground or Open [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 CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) 

    See step  1

    Result

    Result Proceed to
    OK A
    NG (The connector is not connected securely.) B
    NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) C

    Result: 

    B 

    CONNECT SECURELY 

    Result: 

    C 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  2

  2. CHECK CONNECTOR CONNECTION CONDITION (DC/DC CONVERTER ASSEMBLY CONNECTOR) 
    1. Check the connection condition of the DC/DC converter assembly connector and the contact pressure of each terminal.

      HINT: 

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [10/2022 - ]

      OK

      The terminals are not deformed and are connected securely.

      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (DC/DC CONVERTER ASSEMBLY POWER SUPPLY) 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

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

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

    • Disconnect the DC/DC converter assembly connector.
      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      H5-1 (IGCT) - Body ground Ignition switch ON 11 to 14 V V

      HINT: 

      As there might be an intermittent malfunction in the DC/DC converter assembly power source circuit, inspect the following even if the measured voltage is as specified.

      • Installation condition of fuse(s) (before removing fuse(s)) (Power Source Circuit)
      • Fuse condition (before and after removing fuse(s)) (Power Source Circuit)
      • Connection condition of connectors (Power Source Circuit)
      • Wire harness condition (Power Source Circuit)
      • Wire harness condition (GND circuit)

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the DC/DC converter assembly connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HYBRID VEHICLE CONTROL ECU (CHECK WAVEFORM) 

    See step  1

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  5

  5. CLEAR DTC 

    See step  3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  6

  6. CHECK DTC OUTPUT (HYBRID CONTROL) 

    Pre-procedure1

    • None.
    • Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Result

      Result  Proceed to
      P0A08-14 is not output A
      P0A08-14 is output B

    Post-procedure1

    • Turn the ignition switch off.

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ] 

    Result: 

    B 

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

  7. CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE OF VLO INSIDE HYBRID VEHICLE CONTROL ECU) 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    • 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.

    • Disconnect the DC/DC converter assembly connector.
      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H5-6 (VLO) - Body ground Ignition switch off 370 to 430 kΩ kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the DC/DC converter assembly connector.

    Result: 

    OK 

    REPLACE DC/DC CONVERTER ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (DC/DC CONVERTER ASSEMBLY - HYBRID VEHICLE CONTROL ECU) 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    • 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.

    • Disconnect the DC/DC converter assembly connector.
      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    • Disconnect the hybrid vehicle control ECU connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H5-6 (VLO) - A21-35 (VLO) Ignition switch off Below 1 Ω Ω
      H5-6 (VLO) or A21-35 (VLO) - Body ground and other terminals Ignition switch off 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the hybrid vehicle control ECU connector.
    • Reconnect the DC/DC converter assembly connector.

    Result: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

scientia non olet · About LEMON Manuals