Front Fog Light Circuit [08/2019 - ]: 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 [08/2019 - ] 

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. Perform the Active Test according to the display on the Techstream.

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Front Fog Light Relay	Front fog lights	OFF/ON	Light control switch 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 [08/2019 - ] 

Result: 

NG 

See step  3

1. Using a voltmeter, check the signal reading of the semiconductor power integration ECU.

   Refer to ON-VEHICLE INSPECTION [10/2015 - ]

   OK

   Output signal reading is normal.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (RESULTS OF SIGNAL READING CHECK). Refer to  PROCEDURE - Step 2 

Result: 

OK 

See step  4

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the semiconductor power integration ECU from the engine room relay block and junction block assembly.

   Refer to REMOVAL [08/2019 - ]

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A-1 (ALT) - Body ground	Power switch off	11 to 14 V
   B-1 (BATT) - Body ground	Power switch off	11 to 14 V
   1D-11 (FMIG) - Body ground	Power switch on (IG)	11 to 14 V
   1E-4 (TAIL) - Body ground	Power switch off, light control switch in tail or head position	11 to 14 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1D-14 (GND1) - Body ground	Always	Below 1 Ω
   1G-5 (GND2) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Disconnect the 2C 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
   1D-7 (-S) - 2C-25	Always	Below 1 Ω
   1D-7 (-S) or 2C-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  6

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 [08/2019 - ]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   2C-25 - MB-7 (FFGO)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

Result: 

OK 

See step  7

1. Replace the semiconductor power integration ECU with a new one.

   Refer to REMOVAL [08/2019 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  8

1. Check the operation of the front fog lights.

   OK

   Front fog lights operate normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (SEMICONDUCTOR POWER INTEGRATION ECU WAS DEFECTIVE) 

Result: 

NG 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2019 - ]