Taillight Relay Circuit [08/2019 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. Perform the Active Test according to the display on the Techstream.
   MAIN BODY
   
   

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Taillight Relay	Taillight relay	OFF or ON	-

   OK

   Taillights illuminate.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ] 

Result: 

NG 

See step  2

1. Disconnect the 5K and 5H driver side junction block assembly connectors.
2. Disconnect the R25 rear combination light socket and wire sub-assembly LH connector.
3. Disconnect the R26 rear combination light socket and wire sub-assembly RH connector.
4. Disconnect the X6 luggage electrical key switch connector.
5. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   5K-1 - Body ground	Always	11 to 14 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   5H-31 - R26-2 (TL)	Always	Below 1 Ω
   5H-31 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the driver side junction block assembly.

   Refer to REMOVAL [08/2019 - ]

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component without harness connected (Driver Side Junction Block Assembly)

   -

   -

2. Remove the main body ECU (multiplex network body ECU) from the driver side junction block assembly.

   Refer to REMOVAL [08/2019 - ]

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   5H-31 - Battery negative (-) terminal	Battery not connected to 5K-1 and A-14 (TRLY)	Below 1 V
   	Battery positive (+) → 5K-1 Battery negative (-) → A-14 (TRLY)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2019 - ] 

Result: 

NG 

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [08/2019 - ]