Headlight ECU RH Communication Stop Mode [11/2018 - 12/2021]: Procedure

1. Disconnect the cable from the negative (-) battery terminal.
2. Disconnect the headlight ECU sub-assembly RH connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Headlight ECU Sub-assembly RH)

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A12-24 (CANH) - A12-23 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR 

Result: 

OK 

See step  2

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Headlight ECU Sub-assembly RH)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A12-12 (GND) - Body ground	Cable disconnected from negative (-) battery terminal	Below 1 Ω

2. Reconnect the cable to the negative (-) battery terminal.
   NOTE:

   When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

   Refer to INITIALIZATION [11/2018 - 02/2019] , or refer to INITIALIZATION [02/2019 - 10/2019] , or refer to INITIALIZATION [10/2019 - 06/2020] , or refer to INITIALIZATION [06/2020 - 08/2020] , or refer to INITIALIZATION [08/2020 - 12/2021]

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A12-4 (IG) - Body ground	Ignition switch ON	11 to 14 V
   	Ignition switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Headlight ECU Sub-assembly RH)

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A12-13 (ECUB) - Body ground	For approximately 15 seconds after the ignition switch is turned to ON or off	11 to 14 V
   	Approximately 15 seconds elapsed after turning the ignition switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH 

Refer to REMOVAL [11/2018 - 02/2019] , or refer to REMOVAL [02/2019 - 12/2021]

Result: 

NG 

GO TO LIGHTING SYSTEM 

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2018 - 08/2020] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2020 - 12/2021]