Front Fog Light Circuit [10/2014 - 09/2017]: Procedure

1. Using the Techstream, perform the Active Test.

   Refer to DATA LIST / ACTIVE TEST [10/2014 - 09/2017]

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Front Fog Light Relay	Front fog light relay	ON or OFF	The headlight dimmer switch is in the tail position

   Body Electrical > Main Body > Active Test 

   Tester Display
   Front Fog Light Relay

   Result

   Result	Proceed to
   The Active Test is performed normally	A
   The Active Test is not performed normally for both fog lights	B
   The Active Test is not performed normally for the right side fog light only	C
   The Active Test is not performed normally for the left side fog light only	D

Result: 

A 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2014 - 09/2017] 

Result: 

C 

See step  9

Result: 

D 

See step  11

Result: 

B 

See step  2

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Inspect the fog light relay.

   Refer to ON-VEHICLE INSPECTION [10/2014 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE FOG LIGHT RELAY (FOG FR) 

Result: 

OK 

See step  3

1. Remove the front fog light relay from the No. 2 engine room relay block.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Front Fog Light Relay [FOG FR])

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Relay terminal 3 - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Remove the front fog light relay from the No. 2 engine room relay block.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Front Fog Light Relay [FOG FR])

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   Relay terminal 1 - Body ground	Headlight dimmer switch off → TAIL or HEAD (When vehicle has the dimmer switch off position) Headlight dimmer switch in AUTO with low beams off → low beams on	Below 1 V → 11 to 14 V

   If the low beams are illuminated, shine a light on the automatic light control sensor to change the system to daytime mode.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  7

Result: 

OK 

See step  5

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Disconnect the A28 fog light assembly LH connector.
3. Disconnect the A29 fog light assembly RH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 5 - A28-1 (B)	Always	Below 1 Ω
   Relay terminal 5 - A29-1 (B)	Always	Below 1 Ω
   A28-4 (E) - Body ground	Always	Below 1 Ω
   A29-4 (E) - Body ground	Always	Below 1 Ω
   Relay terminal 5 or A28-1 (B) - Body ground	Always	10 kΩ or higher
   Relay terminal 5 or A29-1 (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  6

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Remove the instrument panel junction block assembly.

   Refer to REMOVAL [10/2014 - 05/2019]

3. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Refer to REMOVAL [10/2014 - 05/2019]

4. Disconnect the 4B instrument panel junction block assembly connector.
5. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 2 - A-7 (FFGO)	Always	Below 1 Ω
   Relay terminal 2 or A-7 (FFGO) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [10/2014 - 05/2019] 

Result: 

NG 

See step  8

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Disconnect the 4B instrument panel junction block assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 1 - 4B-25	Always	Below 1 Ω
   Relay terminal 1 or 4B-25 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [10/2014 - 05/2019] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Disconnect the 4B instrument panel junction block assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 2 - 4B-56	Always	Below 1 Ω
   Relay terminal 2 or 4B-56 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [10/2014 - 05/2019] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Disconnect the A29 fog light assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 5 - A29-1 (B)	Always	Below 1 Ω
   A29-4 (E) - Body ground	Always	Below 1 Ω
   Relay terminal 5 or A29-1 (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  10

1. Remove the fog light assembly RH.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Refer to REMOVAL [10/2014 - 09/2017]

2. Remove the fog light unit RH from the fog light assembly RH.

   Refer to DISASSEMBLY [10/2014 - 09/2017]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A-2 - B-1 (B)	Always	Below 1 Ω
   A-3 - B-4 (E)	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE FOG LIGHT UNIT RH. Refer to  DISASSEMBLY [10/2014 - 09/2017] 

Result: 

NG 

REPLACE FOG LIGHT ASSEMBLY RH. Refer to  REMOVAL [10/2014 - 09/2017] 

1. Remove the front fog light relay from the No. 2 engine room relay block.
2. Disconnect the A28 fog light assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Relay terminal 5 - A28-1 (B)	Always	Below 1 Ω
   A28-4 (E) - Body ground	Always	Below 1 Ω
   Relay terminal 5 or A28-1 (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  12

1. Remove the fog light assembly LH.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Refer to REMOVAL [10/2014 - 09/2017]

2. Remove the fog light unit LH from the fog light assembly LH.

   Refer to DISASSEMBLY [10/2014 - 09/2017]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A-2 - B-1 (B)	Always	Below 1 Ω
   A-3 - B-4 (E)	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE FOG LIGHT UNIT LH. Refer to  DISASSEMBLY [10/2014 - 09/2017] 

Result: 

NG 

REPLACE FOG LIGHT ASSEMBLY LH. Refer to  REMOVAL [10/2014 - 09/2017]