Taillight Relay Circuit [08/2015 - 08/2019]: Procedure

1. Using the Techstream, perform the Active Test (Refer to DATA LIST / ACTIVE TEST [08/2015 - 08/2016] , or refer to DATA LIST / ACTIVE TEST [08/2016 - 08/2019] ).
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Taillight Relay	Taillight relay	ON/OFF	-

   OK

   Taillight relay operates (taillights illuminate).

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

(Refer to REMOVAL [08/2015 - 08/2019] )

Result: 

NG 

See step  2

1. Remove the main body ECU (Refer to REMOVAL [08/2015 - 08/2019] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A-14 (TRLY) - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Main Body ECU)

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the driver side junction block assembly (Refer to REMOVAL [08/2015 - 08/2019] ).
2. Remove the main body ECU from the driver side junction block assembly (Refer to REMOVAL [08/2015 - 08/2019] ).
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A-14 (TRLY) - 2K-1	Always	Below 1 Ω

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [08/2015 - 08/2016] , or refer to PROBLEM SYMPTOMS TABLE [08/2016 - 08/2019] )

Result: 

NG 

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY 

(Refer to REMOVAL [08/2015 - 08/2019] )