Taillight Relay Circuit: 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. Check that the relay operates.
   MAIN BODY
   
   

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

   OK

   Taillight relay operates (Taillights illuminate).

NG → See step   2 

OK → See step   4 

1. Disconnect the 3E instrument panel junction block assembly connector.
   Fig 1: Measuring Voltage Of Instrument Panel Junction Block Assembly Connector

   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
   3E-1 - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Instrument Panel Junction Block Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the instrument panel junction block assembly. Refer to REMOVAL .
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
   Fig 2: Measuring Voltage Of Instrument Panel Junction Block Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *a

   Component without harness connected (Instrument Panel Junction Block Assembly)

   -

   -

3. Connect a positive (+) lead from the battery to terminal 3E-1.
4. Connect a negative (-) lead from the battery to terminal MB-14 (TRLY).
5. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   3D-3 - Battery negative terminal	Always	11 to 14 V
   3D-6 - Battery negative terminal	Always	11 to 14 V
   3D-7 - Battery negative terminal	Always	11 to 14 V
   3D-8 - Battery negative terminal	Always	11 to 14 V
   3C-4 - Battery negative terminal	Always	11 to 14 V

NG → See step   6 

OK → See step   5