DESCRIPTION
The main body ECU (instrument panel junction block assembly) receives a front fog light switch information signal from the light control switch (front fog switch), and illuminates the front fog lights.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
As the door control battery is installed between the vehicle battery and main body ECU (instrument panel junction block assembly), first perform the inspections in On-Vehicle Inspection to confirm that there are no malfunctions in the power source circuit for the main body ECU (instrument panel junction block assembly) before performing this troubleshooting procedure.
Tech Tips
Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.
PROCEDURE
CHECK VEHICLE CONDITION
Check the vehicle condition.
Result | Proceed to |
---|---|
Front fog light assembly LH does not turn on | A |
Front fog light assembly RH does not turn on | B |
B |
PERFORM ACTIVE TEST USING GTS (FRONT FOG LIGHT RELAY) Click here |
A |
PERFORM ACTIVE TEST USING GTS (FRONT FOG LIGHT RELAY)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Body Electrical / Main Body / Active Test / Front Fog Light Relay.
Check that the front fog light assembly LH turns on/off.
Tester Display | Test Part | Control Range | Diagnostic Note |
---|---|---|---|
Front Fog Light Relay | Front fog light | ON/OFF | - |
OK |
---|
Front fog light assembly LH turns on/off. |
OK |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here |
NG |
INSPECT FR FOG RELAY LH
Remove the FR FOG RELAY LH from the engine room No. 1 relay block.
Inspect the FR FOG RELAY LH Click here.
NG |
REPLACE FR FOG RELAY LH |
OK |
CHECK HARNESS AND CONNECTOR (FR FOG RELAY LH - BATTERY)
*a | Front view of wire harness connector (to FR FOG RELAY LH) |
Remove the FR FOG RELAY LH from the engine room No. 1 relay block.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
CHECK HARNESS AND CONNECTOR (FR FOG RELAY LH - MAIN BODY ECU [INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY])
Remove the FR FOG RELAY LH from the engine room No. 1 relay block.
Disconnect the D81 main body ECU (instrument panel junction block assembly) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
CHECK HARNESS AND CONNECTOR (FRONT FOG LIGHT ASSEMBLY LH - FR FOG RELAY LH AND BODY GROUND)
Remove the FR FOG RELAY LH from the engine room No. 1 relay block.
Disconnect the A22 front fog light assembly LH connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
OK |
REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
PERFORM ACTIVE TEST USING GTS (FRONT FOG LIGHT RELAY)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Body Electrical / Main Body / Active Test / Front Fog Light Relay.
Check that the front fog light assembly RH turns on/off.
Tester Display | Test Part | Control Range | Diagnostic Note |
---|---|---|---|
Front Fog Light Relay | Front fog light | ON/OFF | - |
OK |
---|
Front fog light assembly RH turns on/off. |
OK |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here |
NG |
INSPECT FR FOG RELAY RH
Remove the FR FOG RELAY RH from the engine room No. 1 relay block.
Inspect the FR FOG RELAY RH Click here.
NG |
REPLACE FR FOG RELAY RH |
OK |
CHECK HARNESS AND CONNECTOR (FR FOG RELAY RH - BATTERY)
*a | Front view of wire harness connector (to FR FOG RELAY RH) |
Remove the FR FOG RELAY RH from the engine room No. 1 relay block.
Measure the voltage according to the value(s) in the table below.
Standard Voltage | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
CHECK HARNESS AND CONNECTOR (FR FOG RELAY RH - MAIN BODY ECU [INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY])
Remove the FR FOG RELAY RH from the engine room No. 1 relay block.
Disconnect the D79*1 or D80*2 main body ECU (instrument panel junction block assembly) connector.
*1: for LHD (w/o Seat Position Memory) and RHD (w/o Theft Deterrent System)
*2: for LHD (w/ Seat Position Memory) and RHD (w/ Theft Deterrent System)
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
|||||||||
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
CHECK HARNESS AND CONNECTOR (FRONT FOG LIGHT ASSEMBLY RH - FR FOG RELAY RH AND BODY GROUND)
Remove the FR FOG RELAY RH from the engine room No. 1 relay block.
Disconnect the A18 front fog light assembly RH connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
OK |
REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |