Front Fog Light Circuit [11/2015 - 12/2018]: Procedure

1. Check the operation of the taillights.

   OK

   Taillights operate normally.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2015 - 12/2018] 

Result: 

OK 

See step  2

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.

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Front Fog Light Relay	Front fog light relay	ON/OFF	Light control switch is in tail position

   Body Electrical > Main Body > Active Test 

   Tester Display
   Front Fog Light Relay

   OK

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

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2015 - 12/2018] 

Result: 

NG 

See step  3

1. Remove the FOG FR relay.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Relay terminal 5 - Body ground	Power switch off	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Relay terminal 2 - Body ground	Power switch off, Taillights on	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  5

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component without harness connected (FOG FR Relay)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Voltage not applied between terminals 1 and 2	10 kΩ or higher
   3 - 5	Voltage applied between terminals 1 and 2	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE FOG FR RELAY 

Result: 

OK 

See step  6

1. Disconnect the A39 fog light assembly LH connector.
2. Disconnect the A38 fog light assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   (A39, A38)

   (A39)

   (A38)

   Tester Connection	Condition	Specified Condition
   Relay terminal 3 - A39-4 (B)	Always	Below 1 Ω
   Relay terminal 3 - A38-4 (B)	Always	Below 1 Ω
   Relay terminal 3 or A39-4 (B) - Body ground	Always	10 kΩ or higher
   Relay terminal 3 or A38-4 (B) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

1. Disconnect the 3A 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
   Relay terminal 1 - 3A-52	Always	Below 1 Ω
   Relay terminal 1 or 3A-52 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  8

1. Remove the instrument panel junction block assembly.

   Refer to REMOVAL [11/2015 - 12/2018]

2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component without harness connected (Instrument Panel Junction Block Assembly)

   -

   -

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3A-52 - MB-7 (FFGO)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2015 - 12/2018] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [11/2015 - 12/2018] 

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
   Relay terminal 2 - 3D-11	Always	Below 1 Ω
   Relay terminal 2 or 3D-11 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [11/2015 - 12/2018] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR