Headlight ECU LH Communication Stop Mode [12/2019 - 11/2023]: Procedure

1. Disconnect the cable from the negative (-) battery terminal.
2. Disconnect the A15 headlight ECU sub-assembly LH connector.
3. 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 LH)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A15-24 (CANH) - A15-23 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

   Result

   Result
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH) 

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 LH)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A15-12 (GND) - Body ground	Cable disconnected from negative (-) battery terminal	Below 1 Ω

2. Reconnect the cable to the negative (-) battery terminal.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A15-4 (IG) - Body ground	Ignition switch ON	11 to 14 V

   Result

   Result
   OK
   NG

Result: 

OK 

REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH 

Refer to REMOVAL [12/2019 - 11/2023]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)