2018 Toyota Prius Prime AdvancedFACTORY OEM SERVICE PROCEDURE

ECU Power Source Circuit [09/2016 - ]: Procedure

  1. CHECK DTC OUTPUT (HEALTH CHECK) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Health Check.
    5. Check DTCs.

      Result

      Result Proceed to
      No DTCs are output A
      DTCs are output B
    6. Turn the power switch off.

    Result: 

    B 

    GO TO DTC CHART 

    Result: 

    A 

    See step  2

  2. CHECK ELECTRIC VEHICLE CHARGER ASSEMBLY (BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Case of electric vehicle charger assembly - Body ground Always Below 1 Ω
      GTY703470Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Electric Vehicle Charger Assembly
      *2 Installation Bolt (for Body Ground)

      HINT: 

      As the electric vehicle charger assembly is grounded through its case, make sure that the ground bolt is tightened to the specified torque.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    TIGHTEN INSTALLATION BOLT. Refer to  PROCEDURE - Step 2 [09/2016 - 05/2019]  , or refer to  PROCEDURE - Step 2 [05/2019 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK ELECTRIC VEHICLE CHARGER ASSEMBLY (AMD2 TERMINAL VOLTAGE) 
    WARNING:

    Be sure to wear insulated gloves.

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

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the Service Information because this may cause a malfunction.

    2. Remove the EV charger duct. (for Type A)

      Refer to PROCEDURE - Step 21 [09/2016 - 05/2019] , or refer to PROCEDURE - Step 28 [05/2019 - 07/2020] , or refer to PROCEDURE - Step 28 [07/2020 - ]

    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      N75-1 (AMD2) - Body ground Always 11 to 14 V
      GTY739741Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Electric Vehicle Charger Assembly)
    5. Disconnect the cable from the negative (-) auxiliary battery terminal.
    6. Install the EV charger duct. (for Type A)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK ELECTRIC VEHICLE CHARGER ASSEMBLY (IGCT VOLTAGE) 
    WARNING:

    Be sure to wear insulated gloves.

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

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the Service Information because this may cause a malfunction.

    2. Remove the EV charger duct. (for Type A)
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Turn the power switch on (IG).
    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      N74-6 (IGCT) - Body ground Power switch on (IG) 11 to 14 V
      GTY730826Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Electric Vehicle Charger Assembly)
    6. Turn the power switch off.
    7. Disconnect the cable from the negative (-) auxiliary battery terminal.
    8. Install the EV charger duct. (for Type A)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO PROBLEM SYMPTOMS TABLE (PLUG-IN CHARGE CONTROL SYSTEM). Refer to  PROBLEM SYMPTOMS TABLE [09/2016 - ] 

    Result: 

    NG 

    See step  6

  5. CHECK FUSE (AMD2) 
    1. Remove the AMD2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
      GTY726455Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 AMD2 Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      AMD2 fuse terminals Always Below 1 Ω
    3. Install the AMD2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    See step  9

  6. CHECK FUSE (IGCT NO. 4) 
    1. Remove the IGCT NO. 4 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
      GTY693864Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 IGCT NO. 4 Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IGCT NO. 4 fuse terminals Always Below 1 Ω
    3. Install the IGCT NO. 4 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - ELECTRIC VEHICLE CHARGER ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves.

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

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the Service Information because this may cause a malfunction.

    2. Remove the IGCT NO. 4 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Remove the EV charger duct. (for Type A)
    4. Disconnect the N74 electric vehicle charger assembly connector.
      GTY736005Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Measure the resistance according to the value(s) in the table below.
      GTY689736Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 IGCT NO. 4 Fuse
      *a Front view of wire harness connector
      (to Electric Vehicle Charger Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      N74-6 (IGCT) - IGCT NO. 4 fuse terminal 2 Always Below 1 Ω
    6. Reconnect the N74 electric vehicle charger assembly connector.
    7. Install the EV charger duct. (for Type A)
    8. Install the IGCT NO. 4 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT RELAY (IGCT SCENE) 
    1. Remove the IGCT SCENE relay from the No. 2 relay block assembly.
      GTY734250Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 Relay Block Assembly
      *2 IGCT SCENE Relay
    2. Measure the resistance according to the value(s) in the table below.
      GTY483225Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 Auxiliary battery voltage not applied between terminals 1 and 2 10 kΩ or higher
      Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω
    3. Install the IGCT SCENE relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    REPLACE RELAY (IGCT SCENE) 

  9. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - ELECTRIC VEHICLE CHARGER ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves.

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

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the Service Information because this may cause a malfunction.

    2. Remove the AMD2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Remove the EV charger duct. (for Type A)
    4. Disconnect the N75 electric vehicle charger assembly connector.
      GTY703356Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Measure the resistance according to the value(s) in the table below.
      GTY712686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 AMD2 Fuse
      *a Front view of wire harness connector
      (to Electric Vehicle Charger Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      N75-1 (AMD2) or AMD2 fuse terminal 2 - Body ground and other terminals Always 10 kΩ or higher
    6. Reconnect the N75 electric vehicle charger assembly connector.
    7. Install the EV charger duct. (for Type A)
    8. Install the AMD2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (AMD2) 

    Result: 

    NG 

    See step  11

  10. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - ELECTRIC VEHICLE CHARGER ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves.

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

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the Service Information because this may cause a malfunction.

    2. Remove the IGCT NO. 4 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Remove the EV charger duct. (for Type A)
    4. Disconnect the N74 electric vehicle charger assembly connector.
      GTY736005Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Measure the resistance according to the value(s) in the table below.
      GTY689736Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 IGCT NO. 4 Fuse
      *a Front view of wire harness connector
      (to Electric Vehicle Charger Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      N74-6 (IGCT) or IGCT NO. 4 fuse terminal 2 - Body ground and other terminals Always 10 kΩ or higher
    6. Reconnect the N74 electric vehicle charger assembly connector.
    7. Install the EV charger duct. (for Type A)
    8. Install the IGCT NO. 4 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (IGCT NO. 4) 

    Result: 

    NG 

    See step  12

  11. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (AMD2) 

  12. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 4) 

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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