LIGHTING SYSTEM > Front Fog Light Circuit

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DESCRIPTION

  1. This circuit is only for vehicles with the daytime running light system or with automatic light control system.

    HINT:
    1. For vehicles with the daytime running light system or with automatic light control system, the exterior lights (headlights, taillights, front fog lights and rear fog light) are controlled by the main body ECU.
    2. For vehicles without the daytime running light system and without automatic light control system, the exterior lights (headlights, taillights, front fog lights, and rear fog light) are not controlled by the main body ECU, so perform troubleshooting according to the Problem Symptoms Table (Click here).

  2. When all of the following conditions are met, the front fog lights come on.
    1. Taillights are turned on by the automatic light control or manual light control.
    2. Front fog light switch is on.
  1. When any of the following conditions is met, the front fog lights turn off.
    1. Front fog light switch is off.
    2. Taillights are off.

      HINT:
      1. Before performing troubleshooting of the front fog light control, check that the taillights operate normally.
      2. If a front fog light on only one side does not illuminate, inspect the front fog light or wire harness that is related to the front fog light.
      3. If both right and left front fog lights do not illuminate, perform the front fog light relay Active Test and read the front fog light switch value in the Data List to determine if the malfunction exists on the switch side or the relay side.


WIRING DIAGRAM


E177345E01


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

1.PERFORM ACTIVE TEST USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Body / Main Body / Active Test.

  1. According to the display on the tester, perform the Active Test.

    Main Body 
    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Front Fog Light Relay
    		Front fog light relay
    		ON or OFF
    		-

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



NG
Go to step 2
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)  

2.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Body / Main Body / Data List.

  1. According to the display on the tester, read the Data List.

    Main Body 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Front Fog Light SW
    		Front fog light switch signal
    ON or OFF
    		ON: Front fog light switch ON
    OFF: Front fog light switch OFF
    		-

    OK:
    Normal conditions listed above are displayed.



NG
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)
OK


3.INSPECT FRONT FOG LIGHT RELAY


    B060778E87

  1. Remove the front fog light relay from the No. 4 relay block.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    3 - 5
    		Voltage is not applied between terminals 1 and 2
    		10 kΩ or higher
    Apply the battery voltage between terminals 1 and 2
    		Below 1 Ω

  1. Reinstall the front fog light relay.



NG
REPLACE FRONT FOG LIGHT RELAY
OK


4.CHECK HARNESS AND CONNECTOR (BATTERY - FRONT FOG LIGHT RELAY)


    E177349E01

  1. Remove the front fog light relay from the No. 4 relay block.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    Front fog light relay terminal 5 - Body ground
    		Always
    		11 to 14 V
    Front fog light relay terminal 2 - Body ground
    		Light control switch OFF → TAIL
    		Below 1 V → 11 to 14 V

Text in Illustration 
*1
Component without relay connected
(No. 4 Relay Block)
*2
FR FOG Relay

  1. Reinstall the front fog light relay.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - FRONT FOG LIGHT RELAY)


    E177350E01

  1. Remove the front fog light relay from the No. 4 relay block.

  1. Disconnect the 3C instrument panel junction block connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Front fog light relay terminal 1 - 3C-29
    		Always
    		Below 1 Ω
    3C-29 - Body ground
    		Always
    		10 kΩ or higher

Text in Illustration 
*1
Front view of wire harness connector
(to Instrument Panel Junction Block)
*2
Component without relay connected
(No. 4 Relay Block)
*3
FR FOG Relay

  1. Reinstall the front fog light relay.

  1. Reconnect the instrument panel junction block connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


6.CHECK HARNESS AND CONNECTOR (FRONT FOG LIGHT - FRONT FOG LIGHT RELAY AND BODY GROUND)


    E177351E01

  1. Remove the front fog light relay from the No. 4 relay block.

  1. Disconnect the A6 or A13 front fog light connector.

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

    Standard Resistance:
    LH Side 
    Tester Connection
    		Switch Condition
    		Specified Condition
    Front fog light relay terminal 3 - A6-2
    		Always
    		Below 1 Ω
    Front fog light relay terminal 3 - Body ground
    		Always
    		10 kΩ or higher
    A6-1 - Body ground
    		Always
    		Below 1 Ω
    RH Side 
    Tester Connection
    		Switch Condition
    		Specified Condition
    Front fog light relay terminal 3 - A13-2
    		Always
    		Below 1 Ω
    Front fog light relay terminal 3 - Body ground
    		Always
    		10 kΩ or higher
    A13-1 - Body ground
    		Always
    		Below 1 Ω

Text in Illustration 
*1
Front view of wire harness connector
(to Front Fog Light)
*2
Component without relay connected
(No. 4 Relay Block)
*3
LH side
*4
RH side
*5
FR FOG Relay

  1. Reinstall the front fog light relay.

  1. Reconnect the front fog light connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


7.REPLACE MAIN BODY ECU

  1. Temporarily replace the main body ECU with a new or normally functioning one (Click here).


NEXT


8.PERFORM ACTIVE TEST USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Body / Main Body / Active Test.

  1. According to the display on the tester, perform the Active Test.

    Main Body 
    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Front Fog Light Relay
    		Front fog light relay
    		ON or OFF
    		-

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



NG
REPLACE INSTRUMENT PANEL JUNCTION BLOCK
OK

END (MAIN BODY ECU DEFECTIVE)