Front Fog Light Circuit [12/2019 - 11/2023]: 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 [12/2019 - 10/2022]  , or refer to  PROBLEM SYMPTOMS TABLE [10/2022 - 11/2023] 

Result: 

OK 

See step  2

1. Perform the Active Test according to the display on the GTS.

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Front Fog Light Relay	Front fog lights	OFF or ON	-

   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 [12/2019 - 10/2022]  , or refer to  PROBLEM SYMPTOMS TABLE [10/2022 - 11/2023] 

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
   2 (FOG FR relay) - Body ground	Ignition switch off*1 Always*2	11 to 14 V
   5 (FOG FR relay) - Body ground	Ignition switch off*1 Always*2	11 to 14 V

   1. *1: for HV Model
   2. *2: for Gasoline Model

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

Refer to ON-VEHICLE INSPECTION [12/2019 - ]

Result

Result: 

NG 

REPLACE FOG FR RELAY 

Result: 

OK 

See step  5

1. Disconnect the A59 fog light assembly LH connector.
2. Disconnect the A58 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
   3 (FOG FR relay) - A59-2 (B)	Always	Below 1 Ω
   3 (FOG FR relay) - A58-2 (B)	Always	Below 1 Ω
   3 (FOG FR relay) or A59-2 (B) - Body ground	Always	10 kΩ or higher
   3 (FOG FR relay) or A58-2 (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. Disconnect the 4C 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
   1 (FOG FR relay) - 4C-25	Always	Below 1 Ω
   1 (FOG FR relay) or 4C-25 - 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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4C-25 - 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 [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]