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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 65 (Hybrid Control System - Diagnostic Codes (5 Of 7)) >> HYBRID CONTROL SYSTEM (for PHEV Model) >> DTC P1CCC-96: DC/DC Converter Enable Component Internal Failure [08/2023 - ] >> Procedure

DTC P1CCC-96: DC/DC Converter Enable Component Internal Failure [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) 

    Pre-procedure1

    1. None.

      Procedure1

    2. Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Powertrain > Motor Generator > Trouble Codes 

      Result

      Result Proceed to
      P1CCC-96 only is output, or DTCs except the ones in the table below are also output. A
      DTCs of hybrid control system in the table below are output. B
      DTCs of motor generator control system in the tables below are output. C
      TABLE 1

      Malfunction Content System Relevant DTC
      Insulation Malfunction Hybrid control system P1C7C-49 Hybrid/EV Battery Voltage System Isolation (A/C Area) Internal Electronic Failure
      P1C7D-49 Hybrid/EV Battery Voltage System Isolation (Hybrid/EV Battery Area) Internal Electronic Failure
      P1C7E-49 Hybrid/EV Battery Voltage System Isolation (Transaxle Area) Internal Electronic Failure
      P1C7F-49 Hybrid/EV Battery Voltage System Isolation (Direct Current Area) Internal Electronic Failure
      P1C80-49 Hybrid/EV Battery Voltage System Isolation (Rear Motor Area) Internal Electronic Failure
      High Voltage Circuit Malfunction Hybrid control system P0AA6-49 Hybrid/EV Battery Voltage System Isolation Internal Electronic Failure
      P0AD9-11 Hybrid/EV Battery Positive Contactor Circuit Short to Ground
      P0ADD-11 Hybrid/EV Battery Negative Contactor Circuit Short to Ground
      P0AE4-11 Hybrid/EV Battery Precharge Contactor Circuit Short to Ground
      P1C84-49 High Voltage Power Resource Circuit Short during Ready ON
      P3004-49 High Voltage Power Resource Circuit Short during Pre-Charge
      System malfunction Hybrid control system P1F32-00 DC/DC Converter Cooling System Performance
      Motor generator control system P0E57-17 DC/DC Converter Voltage Sensor "A"(VL) Circuit Voltage Above Threshold

      HINT: 

      P1CCC-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.)

      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 (MOTOR GENERATOR CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - ] 

    Result: 

    A 

    See step  2

  2. 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  3

  3. CHECK CONNECTOR CONNECTION CONDITION (DC/DC CONVERTER ASSEMBLY CONNECTOR) 
    1. Check the connection condition of the DC/DC converter assembly connectors and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      HINT: 

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

      OK

      - The connector is connected securely.

      - The terminals are not deformed and are connected securely.

      - No water or foreign matter in the connector.

      GTY1203577Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      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  4

  4. INSPECT FUSE (DC/DC) 

    Pre-procedure1

    1. Remove the DC/DC fuse from the No. 1 luggage room relay block and No. 1 junction block assembly.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      DC/DC fuse Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. Install the DC/DC fuse.

    Result: 

    NG 

    REPLACE FUSE (DC/DC) 

    Result: 

    OK 

    See step  5

  5. CHECK AMD TERMINAL VOLTAGE 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    1. Connect the cable to the negative (-) auxiliary battery terminal.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.
      GTY1203966Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      U5-1 (AMD) - Body ground Ignition switch off Same as auxiliary battery voltage

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. Disconnect the cable from the negative (-) auxiliary battery terminal.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK AMD TERMINAL CONNECTION CONDITION 
    WARNING:

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Check for arc marks on the terminals for the AMD terminal (DC/DC converter assembly side and No. 1 luggage room relay block side).
      GTY1205350Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 AMD Terminal (DC/DC Converter Assembly Side)
      *2 AMD Terminal (No. 1 Luggage Room Relay Block Side)

      Procedure1

    3. Check the connection of the AMD terminal (DC/DC converter assembly side and No. 1 luggage room relay block side).

      Torque

      T = 11.5 N.m (117 kgf/cm, 8 ft.lbf) (DC/DC Converter Assembly Side)

      T = 7.6 N.m (77 kgf/cm, 67 in.lbf) (No. 1 Luggage Room Relay Block Side)

      Result

      Result Proceed to
      There are no arc marks. The terminal is connected securely and there are no contact problems. A
      There are no arc marks. The terminal is not connected securely and there is a contact problem. B
      There are arc marks. - C

      Post-procedure1

    4. None.

    Result: 

    B 

    CONNECT SECURELY 

    Result: 

    C 

    REPLACE MALFUNCTIONING PARTS 

    Result: 

    A 

    See step  7

  7. CHECK CONNECTOR CONNECTION CONDITION (NO. 1 JUNCTION BLOCK ASSEMBLY) 

    Pre-procedure1

    1. Check the connection condition of the No. 1 junction block assembly connectors and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      HINT: 

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

      GTY1205307Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      - The connector is connected securely.

      - The terminals are not deformed and are connected securely.

      - No water or foreign matter in the connector.

      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 

    REPLACE MALFUNCTIONING PARTS 

    Result: 

    A 

    See step  8

  8. CHECK CONNECTOR CONNECTION CONDITION (DC/DC CONVERTER ASSEMBLY CONNECTOR) 
    1. Check the connection condition of the DC/DC converter assembly connectors and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      HINT: 

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

      GTY1206199Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      - The connector is connected securely.

      - The terminals are not deformed and are connected securely.

      - No water or foreign matter in the connector.

      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 

    REPLACE MALFUNCTIONING PARTS 

    Result: 

    A 

    See step  9

  9. CHECK NO. 2 HV FLOOR UNDER WIRE 
    WARNING:

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the No. 2 HV floor under wire connector from the DC/DC converter assembly.
      GTY1206199Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the No. 2 HV floor under wire connector from the No. 1 junction block assembly.

      HINT: 

      Make sure that no foreign matter has entered or contaminated the No. 2 HV floor under wire connector.

      GTY1205307Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Procedure1

    4. Using a megohmmeter set to 500 V, measure the insulation resistance according to the value(s) in the table below.
      NOTE:
      • Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.
      • Be sure to inspect with connecting the tester probes to the tips of the terminal.

      Standard Resistance

      Tester Connection Condition Specified Condition
      U2-1 (CEP) - U1-1 (CEP) Ignition switch off Below 1 Ω
      U2-2 (CBP) - U1-2 (CBP) Ignition switch off Below 1 Ω
      GTY1074476Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Shield Ground
      *a No. 2 HV Floor Under Wire
      (No. 1 Junction Block Assembly Side)
      *b No. 2 HV Floor Under Wire
      (DC/DC Converter Assembly Side)

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. Reconnect the No. 2 HV floor under wire connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK NO. 1 JUNCTION BLOCK ASSEMBLY 
    WARNING:

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Check the No. 1 junction block assembly.

      Procedure1

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R10-1 (CBI2) - R12-1 (PB) Ignition switch off Below 1 Ω
      R10-1 (CBI2) - U2-2 (CBP) Ignition switch off Below 1 Ω
      R10-1 (CBI2) - H74-1 (CBP)*1 Ignition switch off Below 1 Ω
      R10-1 (CBI2) - R15-1 (CBP) Ignition switch off Below 1 Ω
      R11-1 (CEI2) - R13-1 (PE) Ignition switch off Below 1 Ω
      R11-1 (CEI2) - U2-1 (CEP) Ignition switch off Below 1 Ω
      R11-1 (CEI2) - H74-2 (CEP)*1 Ignition switch off Below 1 Ω
      R11-1 (CEI2) - R16-1 (CEP) Ignition switch off Below 1 Ω
      1. *1: w/ Voltage Inverter (1500 W)

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None.

    Result: 

    NG 

    REPLACE NO. 1 JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [08/2023 - ] 

    Result: 

    OK 

    See step  11

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

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the DC/DC converter assembly connector.
      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Procedure1

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H5-5 (NODD) - Body ground Ignition switch off 110 to 150 kΩ

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Reconnect the DC/DC converter assembly connector.

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  12

  12. CHECK COOLING SYSTEM 
    1. Check that the DC/DC converter assembly is free from detachments or damage of the cooling system parts.

      OK

      - The No. 1 DC/DC converter intake duct and DC/DC converter cooling exhaust duct are free from detachments or damage

      - The DC/DC converter cooling blower assembly is not damaged

      Result

      Result Proceed to
      OK A
      NG (The duct is loose) B
      NG (The DC/DC converter cooling blower assembly is damaged) C

    Result: 

    B 

    CONNECT SECURELY 

    Result: 

    C 

    REPLACE MALFUNCTIONING PARTS 

    Result: 

    A 

    See step  13

  13. CHECK DC/DC CONVERTER FUNCTION 

    HINT: 

    The current at the AMD terminal cannot be measured directly because of space limitations.

    Measure the current flowing at the auxiliary battery instead.

    Pre-procedure1

    1. Connect the AC/DC 400 A probe of the tester to the positive (+) auxiliary battery cable.
      NOTE:

      Check the probe is installed in the direction as shown in the illustration

    2. Install the service plug grip.
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Turn the ignition switch to ON (READY) and leave the vehicle as it is until the electric current flowing to the auxiliary battery becomes 10 A or less.

      HINT: 

      If the ignition switch turns off immediately after it is turned to ON (READY), auxiliary battery voltage may be low. Recharge the auxiliary battery and perform this procedure again.

      Procedure1

    5. Measure the current flowing from the auxiliary battery with the ignition switch to ON (READY), the headlight position switch and blower motor switch in the HI position, and the rear window defogger turned on.
      GTY434149Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Probe Direction
      *b Current Flowing to Auxiliary Battery
      GTY430831Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Probe Direction
      *b Current Flowing from Auxiliary Battery

      Standard Current

      Item Condition Specified Condition
      Current flowing from auxiliary battery Ignition switch ON (READY)
      (The headlight position switch and blower motor switch are in the HI position, and the rear window defogger is turned on.)      		 0 A or less
      (no current from auxiliary battery)
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Item Condition Specified Condition
      Auxiliary battery voltage Ignition switch ON (READY)
      (The headlight position switch and blower motor switch are in the HI position, and the rear window defogger is turned on.)      		 12.5 to 15 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    7. Turn the ignition switch off.

    Result: 

    OK 

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

    Result: 

    NG 

    See step  15

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

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the DC/DC converter assembly connector.
      GTY1203576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the hybrid vehicle control ECU connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      H5-5 (NODD) - A21-47 (NODD) Ignition switch off Below 1 Ω
      H5-5 (NODD) or A21-47 (NODD) - Body ground and other terminals Ignition switch off 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. Reconnect the hybrid vehicle control ECU connector.
    6. 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 

  15. CHECK NO. 2 HV FLOOR UNDER WIRE 
    WARNING:

    Be sure to wear insulated gloves.

    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 to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Disconnect the No. 2 HV floor under wire connector from the DC/DC converter assembly.
      GTY1206199Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Procedure1

    3. Using a megohmmeter set to 500 V, measure the insulation resistance according to the value(s) in the table below.
      NOTE:
      • Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.
      • Be sure to inspect with connecting the tester probes to the tips of the terminal.

      Standard Resistance

      Tester Connection Condition Specified Condition
      U1-1 (CEP) - Body ground and shield ground Ignition switch off 1 MΩ or higher
      U1-2 (CBP) - Body ground and shield ground Ignition switch off 1 MΩ or higher
      GTY1204697Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Shield Ground
      *a No. 2 HV Floor Under Wire
      (DC/DC Converter Assembly Side)

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. Reconnect the No. 2 HV floor under wire connector.

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE MALFUNCTIONING PARTS 

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