Taillight Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. According to the display on the Techstream, perform the Active Test.
   MAIN BODY
   
   

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

   OK

   Taillight relay operates. (Taillights illuminate.)

NG → See step   2 

OK → See step   6 

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Data List.
5. According to the display on the Techstream, read the Data List.
   MAIN BODY
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Head Light SW (Tail)	Light control switch TAIL signal/ OFF or ON	OFF: Light control switch in neither TAIL nor HEAD ON: Light control switch in TAIL or HEAD	-

   OK

   Normal conditions listed above are displayed.

NG → See step   7 

OK: Go to next step 

1. Disconnect the 3A 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
   3A-1 - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

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

3. Reconnect the instrument panel junction block assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Temporarily replace the main body ECU with a new or normally functioning one. Refer to REMOVAL .

NEXT: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. According to the display on the Techstream, perform the Active Test.
   MAIN BODY
   
   

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

   OK

   Taillight relay operates. (Taillights illuminate.)

NG → REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

OK → END (MAIN BODY ECU DEFECTIVE)