Taillight Relay Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power 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 2E instrument panel junction block assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   2E-1 - Body ground	Always	11 to 14 V

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 1: Inspecting Instrument Panel Junction Block Assembly Connector Terminals

   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 auxiliary battery to terminal 2E-1.
4. Connect a negative (-) lead from the auxiliary battery to terminal MB-14.
5. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   2C-10 - Auxiliary battery negative terminal	Always	11 to 14 V
   2D-18 - Auxiliary battery negative terminal	Always	11 to 14 V
   2B-7 - Auxiliary battery negative terminal	Always	11 to 14 V

NG → See step   6 

OK → See step   5