LIGHTING SYSTEM > Rear Fog Light Circuit

for Preparation Click here


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, perform troubleshooting according to the Problem Symptoms Table (Click here).

  2. When all of the following conditions are met, the rear fog lights come on.
    1. Low beam headlights are turned on by the automatic light control or manual light control.
    2. Front fog lights are on.*1
    3. Rear fog light switch is on.
  1. When any of the following conditions is met, the rear fog lights turn off.
    1. Taillights are off.
    2. Front fog light switch is off*1.
    3. Rear fog light switch is off.
  1. Before performing troubleshooting of the rear fog light control, check that the low beam headlights and front fog lights*1 operate normally.

    HINT:
    *1: w/ Front Fog Light


WIRING DIAGRAM


E177343E01


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses and bulb 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. Turn the light control switch to the HEAD position.

  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
    Rear Fog Light Relay
    		Rear fog light relay
    		ON or OFF
    		-

    OK:
    Rear fog light relay operates. (Rear fog light comes 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
    Rear Fog Light SW
    		Rear fog light switch signal
    ON or OFF
    		ON: Rear fog light switch ON
    OFF: Rear 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.CHECK HARNESS AND CONNECTOR (REAR FOG LIGHT - JUNCTION BLOCK AND BODY GROUND)


    E177344E01

  1. Disconnect the G42 or G41 rear fog light connector.

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

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

    Standard Resistance:
    for LHD 
    Tester Connection
    		Condition
    		Specified Condition
    3E-19 - G42-1
    		Always
    		Below 1 Ω
    3E-19 or G42-1 - Body ground
    		Always
    		10 kΩ or higher
    G42-2 - Body ground
    		Always
    		Below 1 Ω
    for RHD 
    Tester Connection
    		Condition
    		Specified Condition
    3E-19 - G41-1
    		Always
    		Below 1 Ω
    3E-19 or G41-1 - Body ground
    		Always
    		10 kΩ or higher
    G41-2 - Body ground
    		Always
    		Below 1 Ω

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Instrument Panel Junction Block)
    *2
    		Front view of wire harness connector
    (to Rear Fog Light)
    *3
    		for LHD
    *4
    		for RHD

  1. Reconnect the rear fog light connector.

  1. Reconnect the instrument panel junction block connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.REPLACE MAIN BODY ECU

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


NEXT


5.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. Turn the light control switch to the HEAD position.

  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
    Rear Fog Light Relay
    		Rear fog light relay
    		ON or OFF
    		-

    OK:
    Rear fog light relay operates. (Rear fog light comes on.)



NG
REPLACE INSTRUMENT PANEL JUNCTION BLOCK
OK

END (MAIN BODY ECU DEFECTIVE)