Front Fog Light Circuit

LIGHTING (EXT): LIGHTING SYSTEM: Front Fog Light Circuit
- Front Fog Light Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the front fog lights via the engine room junction block assembly.

WIRING DIAGRAM





INSPECTION PROCEDURE

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

PROCEDURE

1. CHECK OPERATION (TAILLIGHTS AND HEADLIGHTS)

(a) Check the operation of the taillights and headlights.

OK:

Taillights and headlights operate normally.

NG -- GO TO PROBLEM SYMPTOMS TABLE Problem Symptoms Table
OK -- Continue to next step.

2. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Active Test.

(e) Check that the relay operates.

Main Body





OK:

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

NG -- CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Problem Symptoms Table

3. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Using a voltmeter, check the signal reading of the engine room junction block assembly Testing and Inspection.

OK:

Output signal reading is normal.

NG -- INSPECT ENGINE ROOM RELAY BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) Testing and Inspection
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE AND BODY GROUND) Daytime Running Light Relay Circuit

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the 3D instrument panel junction block assembly connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

6. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly Removal.

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





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

Standard Resistance:





(d) Connect a positive (+) lead from the auxiliary battery to terminal 3E-1.

(e) Connect a negative (-) lead from the auxiliary battery to terminal MB-14.

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

Standard Voltage:





Text in Illustration





NG -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Removal
OK -- Continue to next step.

7. CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Replace the engine room junction block assembly with a new or a known good one Removal.

(b) Check that the fog lights operate normally.

OK:

The fog lights operate normally.

NG -- REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Removal

OK -- END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE)