Front Fog Light Circuit [10/2014 - 10/2015]: Procedure

1. Check the operation of the taillights.

   OK

   Taillights operate normally.

Result: 

NG 

GO TO PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] )

Result: 

OK 

See step  2

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
   Front Fog Light Relay	Front fog light relay	ON/OFF	Light control switch is in tail position

   OK

   Front fog light relay operates (Front fog lights come on).

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] )

Result: 

NG 

See step  3

1. Using a voltmeter, check the signal reading of the engine room junction block assembly (Refer to ON-VEHICLE INSPECTION [10/2014 - 10/2015] ).

   OK

   Output signal reading is normal.

Result: 

NG 

INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) 

(Refer to PROCEDURE - Step 2 )

Result: 

OK 

See step  4

1. Remove the engine room junction block assembly from the engine room relay block and junction block assembly (Refer to REMOVAL [10/2014 - ] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *a

   Component without engine room junction block assembly connected (Engine Room Relay Block and Junction Block Assembly)

   -

   -

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A-1 (BATT) - Body ground	Always	11 to 14 V
   B-1 (ALT) - Body ground	Always	11 to 14 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1F-3 (GND1) - Body ground	Always	Below 1 Ω
   1G-4 (GND2) - Body ground	Always	Below 1 Ω

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Disconnect the 3D instrument panel junction block assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1G-2 (TAIL) - 3D-9	Always	Below 1 Ω
   3D-9 - Body ground	Always	10 kΩ or higher
   1F-13 (FOGS) - 3D-38	Always	Below 1 Ω
   3D-38 - Body ground	Always	10 kΩ or higher

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Remove the instrument panel junction block assembly (Refer to REMOVAL [10/2014 - ] ).
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   MB-13 (FFGO) - 3D-38	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   3D-9 - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Instrument Panel Junction Block Assembly)

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

OK 

See step  7

1. Replace the engine room junction block assembly with a new or known good one (Refer to REMOVAL [10/2014 - ] ).
2. Check that the fog lights operate normally.

   OK

   The fog lights operate normally.

Result: 

OK 

END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE) 

Result: 

NG 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

(Refer to REMOVAL [10/2014 - ] )