DESCRIPTION
The main body ECU (multiplex network body ECU) controls the front fog lights via the engine room junction block assembly.
The main body ECU (multiplex network body ECU) controls the front fog lights via the FR FOG relay.
WIRING DIAGRAM
except 6AR-FSE:
for 6AR-FSE:
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.
PROCEDURE
CONFIRM MODEL
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
PERFORM ACTIVE TEST USING GTS Click here |
| A |
|
CHECK OPERATION (TAILLIGHTS)
Check the operation of the taillights.
| OK |
|---|
| Taillights operate normally. |
| NG |
|
GO TO PROBLEM SYMPTOMS TABLE Click here |
| OK |
|
PERFORM ACTIVE TEST USING GTS
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Main Body / Active Test.
Perform the Active Test according to the display on the GTS.
| Tester Display | Test Part | Control Range | Diagnostic Note |
|---|---|---|---|
| Front Fog Light Relay | Front fog light relay | ON/OFF | Light control switch is in tail position |
| OK |
|---|
| Front fog light relay operates. (Front fog lights come on.) |
| OK |
|
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here |
| NG |
|
CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY
Using a voltmeter, check the signal reading of the engine room junction block assembly Click here.
| OK |
|---|
| Output signal reading is normal. |
| NG |
|
INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (RESULTS OF SIGNAL READING CHECK) Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY POWER SOURCE AND BODY GROUND)
Remove the engine room junction block assembly from the engine room relay block and junction block assembly Click here.
| *a | Component without engine room junction block assembly connected (Engine Room Relay Block and Junction Block Assembly) |
- | - |
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
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 (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)
Disconnect the 3D 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 |
|
INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
Remove the instrument panel junction block assembly Click here.
Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Connect a positive (+) lead from the battery to terminal 3E-1*1 or 3F-1*2.
Connect a negative (-) lead from the battery to terminal MB-14 (TRLY).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
*1: for LHD
*2: for RHD
| *A | for LHD |
| *B | for RHD |
| *a | Component without harness connected (Instrument Panel Junction Block Assembly) |
| NG |
|
REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here |
| OK |
|
CHECK ENGINE ROOM JUNCTION BLOCK ASSEMBLY
Replace the engine room junction block assembly with a new or known good one Click here.
Check that the fog lights operate normally.
| OK |
|---|
| The fog lights operate normally. |
| OK |
|
END (ENGINE ROOM JUNCTION BLOCK ASSEMBLY WAS DEFECTIVE) |
| NG |
|
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here |
PERFORM ACTIVE TEST USING GTS
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Main Body / Active Test.
Perform the Active Test according to the display on the GTS.
| Tester Display | Test Part | Control Range | Diagnostic Note |
|---|---|---|---|
| Front Fog Light Relay | Front fog light relay | ON/OFF | Light control switch is in tail position |
| OK |
|---|
| Front fog light relay operates. (Front fog lights come on.) |
| OK |
|
GO TO PROBLEM SYMPTOMS TABLE Click here |
| NG |
|
INSPECT FR FOG RELAY
| *a | Component without harness connected (FR FOG Relay) |
Remove the FR FOG relay from the engine room relay block and junction block assembly.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
REPLACE FR FOG RELAY |
| OK |
|
CHECK HARNESS AND CONNECTOR (POWER SOURCE - FR FOG RELAY)
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
GO TO STOP AND START SYSTEM Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (FR FOG RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)
Disconnect the 3D 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 |
|
INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
Remove the instrument panel junction block assembly Click here.
| *a | Component without harness connected (Instrument Panel Junction Block Assembly) |
Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
| NG |
|
REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (FR FOG RELAY - FOG LIGHT ASSEMBLY LH AND FOG LIGHT ASSEMBLY)
Disconnect the A5 fog light assembly LH connector.
Disconnect the A48 fog light assembly RH connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| OK |
|
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |