LIGHTING SYSTEM Rear Fog Light Circuit

DESCRIPTION

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

  Tech Tips

  
  

  • 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.

  • 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.

• When all of the following conditions are met, the rear fog lights come on.




• Low beam headlights are turned on by the automatic light control or manual light control.

• Front fog lights are on.*1

• Rear fog light switch is on.

• When any of the following conditions is met, the rear fog lights turn off.




• Taillights are off.

• Front fog light switch is off*1.

• Rear fog light switch is off.

• Before performing troubleshooting of the rear fog light control, check that the low beam headlights and front fog lights*1 operate normally.

  Tech Tips

  *1: w/ Front Fog Light

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

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

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

   6. 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

   READ VALUE USING INTELLIGENT TESTER Click here

   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.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

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

   5. 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)

   
   
   1. 

      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

      Disconnect the G42 or G41 rear fog light connector.

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

   3. 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

   4. Reconnect the rear fog light connector.

   5. 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.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

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

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

   6. 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)