ECU Power Source Circuit [08/2023 - ]: Procedure

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. Connect the SST.

   Refer to Instructions for Connecting SST [08/2023 - ] 

3. Disconnect the battery ECU assembly connector.
   NOTE:

   Before disconnecting the connector, check that it is not loose or disconnected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

4. Connect the cable to the negative (-) auxiliary battery terminal.
5. Turn the ignition switch to ON.
6. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   o5-5 (IGCT) - Body ground	Ignition switch ON	11 to 14 V
   o5-18 (IGC2) - Body ground	Ignition switch ON	11 to 14 V

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Battery ECU Assembly)

   NOTE:

   • Turning the ignition switch to ON with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.
   • If the ignition switch is turned to ON with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.
7. Turn the ignition switch off.
8. Disconnect the cable from the negative (-) auxiliary battery terminal.
9. Reconnect the battery ECU assembly connector.
10. Disconnect the SST.

    Result

    Proceed to
    OK
    NG

Result: 

NG 

See step  3

Result: 

OK 

See step  2

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 battery ECU assembly connector.
   NOTE:

   Before disconnecting the connector, check that it is not loose or disconnected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   o5-25 (GND) - Body ground	Always	Below 1 Ω
   o5-26 (GND1) - Body ground	Always	Below 1 Ω
   o5-27 (GND2) - Body ground	Always	Below 1 Ω

4. Reconnect the battery ECU assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block and No. 2 junction block assembly.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   IGCT NO. 2 fuse	Always	Below 1 Ω

3. Install the IGCT NO. 2 fuse to the No. 2 engine room relay block and No. 2 junction block assembly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  6

Result: 

OK 

See step  4

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. Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block and No. 2 junction block assembly.
3. Connect the SST.

   Refer to Instructions for Connecting SST [08/2023 - ] 

4. Disconnect the battery ECU assembly connector.
   NOTE:

   Before disconnecting the connector, check that it is not loose or disconnected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   o5-5 (IGCT) - 2 (IGCT NO. 2 fuse holder)	Always	Below 1 Ω

6. Reconnect the battery ECU assembly connector.
7. Disconnect the SST.
8. Install the IGCT NO. 2 fuse to the No. 2 engine room relay block and No. 2 junction block assembly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block and No. 2 junction block assembly.
2. Remove the IGCT SCENE relay from the No. 1 luggage room relay block and No. 1 junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   5 (IGCT SCENE relay holder) - 1 (IGCT NO. 2 fuse holder)	Always	Below 1 Ω

4. Install the IGCT SCENE relay to the No. 1 luggage room relay block and No. 1 junction block assembly.
5. Install the IGCT NO. 2 fuse to the No. 2 engine room relay block and No. 2 junction block assembly.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

CHECK ECU POWER SOURCE CIRCUIT (HYBRID CONTROL SYSTEM). Refer to  ECU Power Source Circuit [08/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

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. Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block and No. 2 junction block assembly.
3. Connect the SST.

   Refer to Instructions for Connecting SST [08/2023 - ] 

4. Disconnect the battery ECU assembly connector.
   NOTE:

   Before disconnecting the connector, check that it is not loose or disconnected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   o5-5 (IGCT) or 2 (IGCT NO. 2 fuse holder) - Body ground and other terminals	Always	Below 1 Ω

6. Reconnect the battery ECU assembly connector.
7. Disconnect the SST.
8. Install the IGCT NO. 2 fuse to the No. 2 engine room relay block and No. 2 junction block assembly.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE FUSE (IGCT NO. 2) 

Result: 

NG 

See step  7

Result

Result: 

NEXT 

REPLACE FUSE (IGCT NO. 2)