Problem Symptoms Table

WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

Headlight system:

HEADLIGHT SYSTEM PROBLEM SYMPTOMS

Symptom	Suspected area
One side LO-beam headlight does not illuminate	1. H-LP L LWR fuse or H-LP R LWR fuse
	2. Bulb
	3. Light control ECU
	4. Wire harness
Both left and right LO-beam headlights do not illuminate	1. HEAD LP relay
	2. Headlight relay circuit
	3. Light control switch circuit
	4. Headlight signal circuit
	5. Front controller (Engine room No. 2 R/B)
	6. Main body ECU RH (Cowl side J/B RH)
Without HID headlight: One side HI-beam headlight does not illuminate	1. Bulb
	2. Wire harness
With HID headlight: One side HI-beam headlight does not illuminate	1. Bulb
	2. Wire harness
	3. Front controller (Engine room No. 2 R/B)
Both left and right HI-beam headlights do not illuminate	1. H-LP UPR fuse
	2. Headlight (HI-BEAM) circuit
	3. Light control switch circuit
	4. Headlight signal circuit
	5. Front controller (Engine room No. 2 R/B)
	6. Main body ECU RH (Cowl side J/B RH)
"Flash" headlight does not illuminate	1. Light control switch circuit
	2. Main body ECU RH (Cowl side J/B RH)
	3. Front controller (Engine room No. 2 R/B)
When headlight dimmer switch is moved to HI-beam position, LO-beam of discharge headlights remains on, but illumination area of discharge headlights is not increased. (Bi-function does not work.)	1. Headlight solenoid circuit
	2. Front controller (Engine room No. 2 R/B)
	3. Headlight assembly

Daytime running light system:

DAYTIME RUNNING LIGHT SYSTEM

Symptom	Suspected area
Daytime running light system does not operate	1. Light control switch circuit
	2. Parking brake switch
	3. Front controller (Engine room No. 2 R/B)
	4. Main body ECU RH (Cowl side J/B RH)

Taillight system:

TAILLIGHT SYSTEM

Symptom	Suspected area
Parking light does not operate	1. Bulb
	2. Wire harness
	3. Headlight assembly
One side taillight does not illuminate	1. Rear combination light assembly
One side taillight does not illuminate	2. Wire harness
Taillight system does not operate (Taillights, front side marker lights, parking lights, license plate lights, and side marker lights do not illuminate)	1. FR TAIL fuse
	2. Taillight circuit
	3. Light control switch circuit
	4. Front controller (Engine room No. 2 R/B)
	5. Main body ECU LH (Cowl side J/B LH)

Side marker system:

SIDE MARKER SYSTEM

Symptom	Suspected area
Front side marker light does not illuminate	1. Headlight assembly
Rear side marker light does not illuminate	1. Rear combination light assembly

Stop light system:

STOP LIGHT SYSTEM

Symptom	Suspected area
Stop light system does not operate	1. STOP SW fuse
	2. Stop light switch
	3. BRK-LP relay
	4. Rear combination light
	5. Wire harness
One side stop light does not illuminate	1. Rear combination light
One side stop light does not illuminate	2. Wire harness
Hi-mounted stop light does not illuminate	1. Hi mounted stop light assembly
Hi-mounted stop light does not illuminate	2. Wire harness

Front fog light system:

FRONT FOG LIGHT SYSTEM

Symptom	Suspected area
One side fog light does not illuminate	1. Bulb
	2. Front fog light circuit
	3. Fog light assembly
Both left and right fog lights do not illuminate	1. FR FOG fuse
	2. FR FOG relay
	3. Front fog light circuit
	4. Light control switch circuit
	5. Front controller (Engine room No. 2 R/B)
	6. Main body ECU RH (Cowl side J/B RH)

Turn signal light system:

TURN SIGNAL LIGHT SYSTEM

Symptom	Suspected area
Hazard warning light does not operate	1. TURN-HAZ fuse
	2. LH-IG fuse
	3. Turn signal flasher
	4. Hazard warning switch
	5. Hazard warning switch circuit
	6. Turn signal light circuit
	7. Main body ECU RH (Cowl side J/B RH)
One side turn signal light does not operate	1. Bulb
	2. Turn signal flasher
	3. Turn signal light circuit
	4. Headlight assembly
	5. Rear combination light assembly
	6. Main body ECU LH (Cowl side J/B LH)
All turn signal lights do not flash	1. TURN-HAZ fuse
	2. LH-IG fuse
	3. Turn signal light circuit
	4. Light control switch circuit
	5 Hazard warning switch
	6. Main body ECU LH (Cowl side J/B LH)
All turn signal lights do not flash at the correct speed	1. Bulb
	2. Turn signal flasher
	3. Side turn signal light
	4. Headlight assembly
	5. Rear combination light assembly
	6. Wire harness

Buck-up light system:

BUCK-UP LIGHT SYSTEM

Symptom	Suspected area
One side back-up light does not illuminate	1. Bulb
One side back-up light does not illuminate	2. Wire harness
Both left and right back-up lights do not illuminate	1. LH-IG fuse
	2. Buck-up light switch (for M/T)
	3. Park/Neutral position switch (for A/T)
	4. Wire harness

License plate light system:

LICENSE PLATE LIGHT SYSTEM

Symptom	Suspected area
One side license plate light does not illuminate	1. License plate light
One side license plate light does not illuminate	2. Wire harness
Both left and right license plate lights do not illuminate	1. TAIL fuse
	2. License plate light
	3. Wire harness

Interior light system:

INTERIOR LIGHT SYSTEM

Symptom	Suspected area
Front personal lights do not illuminate	1. Bulb
	2. DOME fuse
	3. Overhead J/B (Personal light)
	4. Wire harness
Rear personal lights do not illuminate	1. DOME fuse
	2. Rear room light assembly (Personal light)
	3. Wire harness
Seat illumination does not illuminate	1. Bulb
	2. DOME fuse
	3. Seat illumination circuit
	4. Interior light switch signal circuit
	5. Rear room light assembly
	6. Overhead J/B (Interior light switch)
	7. Main body ECU RH (Cowl side J/B RH)
	8. Main body ECU LH (Cowl side J/B LH)
Door courtesy lights do not illuminate	1. DOME fuse
	2. Door courtesy light
	3. Door courtesy switch
	4. Door courtesy switch circuit
	5. Interior light switch signal circuit
	6. Overhead J/B (Interior light switch)
	7. Main body ECU RH (Cowl side J/B RH)
Scuff plate lights do not illuminate	1. DOME fuse
	2. Scuff plate light
	3. Scuff plate light circuit
	4. Interior light switch signal circuit
	5. Overhead J/B (Interior light switch)
	6. Main body ECU LH (Cowl side J/B LH)
	7. Main body ECU RH (Cowl side J/B RH)
Shift illumination does not illuminate	1. DOME fuse
	2. Shift illumination circuit
	3. Overhead J/B
	4. Main body ECU LH (Cowl side J/B LH)
	5. Main body ECU RH (Cowl side J/B RH)
Glove box light does not illuminate	1. ACC fuse
	2. Glove box light
	3. Wire harness
Foot well lights do not illuminate	1. DOME fuse
	2. Footwell light
	3. Footwell light circuit
	4. Main body ECU RH (Cowl side J/B RH)
Resister illumination does not illuminate	1. PANEL fuse
	2. Resister illumination
	3. Wire harness
Console box light does not illuminate	1. ACC fuse
	2. Console box light
	3. Wire harness
Luggage compartment room light does not illuminate	1. Bulb
	2. DOME fuse
	3. Luggage compartment room light
	4. Wire harness

Others:

SYMPTOM CHART

Symptom	Suspected area
Vanity light does not illuminate	1. Bulb
	2. Visor assembly
	3. Wire harness
Battery saving function does not operate	1. Main body ECU LH (Cowl side J/B LH)
Battery saving function does not operate	2. Main body ECU RH (Cowl side J/B RH)
Door mirror foot lights do not illuminate	1. DOME fuse
	2. Door mirror foot light
	3. Door mirror foot light circuit
	4. Interior light switch signal circuit
	5. Overhead J/B (Interior light switch)
	6. Main body ECU LH (Cowl side J/B LH)
	7. Main body ECU RH (Cowl side J/B RH)

AFS

AFS SYMPTOM CHART

Symptom

Suspected area

AFS does not operate (⁽¹⁾)

1. AFS ECU power source circuit

2. AFS ECU

3. Combination meter assembly

Only one swivel motor is not initialized (⁽¹⁾)

1. Headlight assembly or swivel motor stuck (⁽²⁾)

2. Headlight swivel motor malfunction

3. AFS ECU

Only swivel control does not operate or malfunctions

1. AFS ECU switch status (⁽³⁾)

2. Vehicle speed sensor malfunction

3. BEAN communication malfunction

4. Headlight swivel motor malfunction

5. AFS ECU

Swivel control and leveling control do not operate

1. Height control sensor malfunction

2. Headlight swivel motor malfunction

3. AFS ECU

AFS OFF indicator light does not come on

1. AFS OFF switch circuit

2. AFS ECU

3. Combination meter assembly

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.