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Problem Symptoms Table

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

Use the table below to help determine the cause of problem symptoms If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table Check each symptom by checking the suspected areas in the order they are listed Replace parts as necessary

Headlight System 

PROBLEM SYMPTOMS - HEADLIGHT SYSTEM

Symptom Suspected Area See
One LO-beam headlight does not illuminate H-LP L LWR fuse or H-LP R LWR fuse -
Bulb -
Light control ECU HEADLIGHT ASSEMBLY 
Wire harness -
Both left and right LO-beam headlights do not illuminate HEAD LP relay RELAY 
Headlight relay circuit HEADLIGHT RELAY CIRCUIT 
Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Headlight signal circuit HEADLIGHT SIGNAL CIRCUIT 
Front controller (Multiplex Network Body ECU) -
Main body ECU RH (Cowl side junction block RH) -
One H I-beam headlight does illuminate Bulb -
Wire harness -
Front controller (Multiplex Network Body ECU) -
Both left and right Hl-beam headlights do not illuminate FR CTRL-B fuse -
Headlight (HI-BEAM) circuit HEADLIGHT (HI-BEAM) CIRCUIT 
Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Headlight signal circuit HEADLIGHT SIGNAL CIRCUIT 
Front controller (Multiplex Network Body ECU) -
Main body ECU RH (Cowl side junction block RH) -
"Flash" headlight does not illuminate Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Main body ECU RH (Cowl side junction block RH) -
Front controller (Multiplex Network Body ECU) -
When headlight dimmer switch is moved to Hl-beam position, LO-beam of discharge headlights remains on, illumination area of discharge headlights is not increased (Bi-function does not work) Headlight solenoid circuit HEADLIGHT SOLENOID CIRCUIT 
Front controller (Multiplex Network Body ECU) -
Headlight assembly -

Daytime Running Light System 

PROBLEM SYMPTOMS - DAYTIME RUNNING LIGHT SYSTEM

Symptom Suspected Area See
Daytime running light system does not operate Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Parking brake switch INSPECTION
Front controller (Multiplex Network Body ECU) -
Main body ECU RH (Cowl side junction block RH) -

Taillight System 

PROBLEM SYMPTOMS - TAILLIGHT SYSTEM

Symptom Suspected Area See
Parking light does not operate Bulb -
Wire harness -
One taillight does not illuminate Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 
Rear light assembly REAR LIGHT ASSEMBLY 
Wire harness -
Taillight system does not operate (Taillights, front side marker lights, parking lights, license plate lights, and side marker lights do not illuminate) TAIL fuse and FR TAIL fuse -
Taillight circuit TAILLIGHT CIRCUIT 
Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Front controller (Multiplex Network Body ECU) -
Main body ECU LH (Cowl side junction block LH) -
Main body ECU RH (Cowl side junction block RH) -

Side Marker System 

PROBLEM SYMPTOMS - SIDE MARKER SYSTEM

Symptom Suspected Area See
Front side marker light does not illuminate Headlight assembly HEADLIGHT ASSEMBLY 
Rear side marker light does not illuminate Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 

Stop Light System 

PROBLEM SYMPTOMS - STOP LIGHT SYSTEM

Symptom Suspected Area See
Stop light system does not operate STOP SW fuse -
Stop light switch STOP LIGHT SWITCH 
Stop light control relay STOP LIGHT CONTROL RELAY 
BRK-LP relay RELAY
Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 
Wire harness -
One side stop light does not illuminate Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 
Wire harness -
High mounted stop light does not illuminate High mounted stop light assembly HIGH MOUNTED STOP LIGHT ASSEMBLY 
Wire harness -

Front Fog Light System 

PROBLEM SYMPTOMS - FRONT FOG LIGHT SYSTEM

Symptom Suspected Area See
One fog light does not illuminate Bulb -
Wire harness -
Both left and right fog lights do not illuminate FR FOG fuse -
Front fog light circuit FRONT FOG LIGHT CIRCUIT 
Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Front controller (Multiplex Network Body ECU) -
Main body ECU RH (Cowl side junction block RH) -

Turn Signal Light System 

PROBLEM SYMPTOMS - TURN SIGNAL LIGHT SYSTEM

Symptom Suspected Area See
Hazard warning light does not operate TURN-HAZ fuse -
LH-IG fuse -
Turn signal flasher assembly TURN SIGNAL FLASHER ASSEMBLY 
Hazard warning switch HAZARD WARNING SWITCH 
Turn signal light circuit TURN SIGNAL LIGHT CIRCUIT 
Wire harness -
Main body ECU RH (Cowl side junction block RH) -
One turn signal light does not operate Bulb -
Turn signal flasher assembly TURN SIGNAL FLASHER ASSEMBLY 
Turn signal light circuit TURN SIGNAL LIGHT CIRCUIT 
Headlight assembly HEADLIGHT ASSEMBLY 
Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 
Main body ECU LH (Cowl side junction block LH) -
All turn signal lights do not flash TURN-HAZ fuse -
LH-IG fuse -
Turn signal light circuit TURN SIGNAL LIGHT CIRCUIT 
Light control switch circuit LIGHT CONTROL SWITCH CIRCUIT 
Hazard warning switch HAZARD WARNING SWITCH 
Main body ECU LH (Cowl side junction block LH) -
All turn signal lights do not flash at the correct speed Bulb -
Turn signal flasher assembly TURN SIGNAL FLASHER ASSEMBLY 
Headlight assembly HEADLIGHT ASSEMBLY 
Rear combination light assembly REAR COMBINATION LIGHT ASSEMBLY 
Wire harness -

Back-up Light System 

PROBLEM SYMPTOMS - BACK-UP LIGHT SYSTEM

Symptom Suspected Area See
One back-up light does not illuminate Bulb -
Wire harness -
Both left and right back-up lights do not illuminate LH-IG fuse -
Park/Neutral position switch INSPECTION
Wire harness -

License Plate Light System 

PROBLEM SYMPTOMS - LICENSE PLATE LIGHT SYSTEM

Symptom Suspected Area See
One license plate light does not illuminate License plate light assembly LICENSE PLATE LIGHT ASSEMBLY 
Wire harness -
Both left and right license plate lights do not illuminate TAIL fuse -
License plate light assembly LICENSE PLATE LIGHT ASSEMBLY 
Wire harness -

Door Mirror Foot Light System 

PROBLEM SYMPTOMS - DOOR MIRROR FOOT LIGHT SYSTEM

Symptom Suspected Area See
Door mirror foot lights do not illuminate DOME fuse -
Door mirror foot light OUTER REAR VIEW MIRROR
Door mirror foot light circuit DOOR MIRROR FOOT LIGHT CIRCUIT 
Interior light switch signal circuit INTERIOR LIGHT SWITCH SIGNAL CIRCUIT
Overhead junction block (Interior light switch) PERSONAL LIGHT
Main body ECU LH (Cowl side junction block LH) -
Main body ECU RH (Cowl side junction block RH) -

AFS 

PROBLEM SYMPTOMS - AFS

Symptom Suspected Area See
AFS does not operated*1 AFS ECU power source circuit AFS ECU POWER SOURCE CIRCUIT 
AFS ECU AFS ECU 
Combination meter assembly COMBINATION METER
Only one swivel motor is not initialized*1 Headlight assembly or swivel motor stuck*2 DTC B2412 HEADLIGHT SWIVEL MOTOR LH MALFUNCTION; DTC B2413 HEADLIGHT SWIVEL MOTOR RH MALFUNCTION 
Headlight swivel motor malfunction DTC B2412 HEADLIGHT SWIVEL MOTOR LH MALFUNCTION; DTC B2413 HEADLIGHT SWIVEL MOTOR RH MALFUNCTION 
AFS ECU AFS ECU 
Only swivel control does not operate or malfunctions AFS OFF switch status*3 AFS OFF SWITCH CIRCUIT 
Vehicle speed sensor malfunction DTC B2415 VEHICLE SPEED SENSOR MALFUNCTION 
BEAN communication malfunction DTC B2419 BEAN COMMUNICATION MALFUNCTION 
Headlight swivel motor malfunction DTC B2412 HEADLIGHT SWIVEL MOTOR LH MALFUNCTION; DTC B2413 HEADLIGHT SWIVEL MOTOR RH MALFUNCTION 
AFS ECU AFS ECU 
Swivel control and leveling control do not operate Height control sensor malfunction DTC B2416 HEIGHT CONTROL SENSOR MALFUNCTION 
Headlight swivel motor malfunction DTC B2412 HEADLIGHT SWIVEL MOTOR LH MALFUNCTION; DTC B2413 HEADLIGHT SWIVEL MOTOR RH MALFUNCTION 
AFS ECU AFS ECU 
AFS OFF indicator light does not come on AFS OFF switch circuit AFS OFF SWITCH CIRCUIT 
AFS ECU AFS ECU 
Combination meter assembly COMBINATION METER
HINT:
  • *1: When the AFS indicator light does not come on or blink despite the symptom being occurring, check the battery voltage.
  • *2: Check if the headlight swivel motor turns smoothly by hand. If the motor does not turn, replace it with a new one. If the motor still does not turn, replace the headlight assembly with a new one.
  • *3: Before beginning diagnosis, check that the AFS setting is ON.