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Home >> Lexus >> 2014 >> IS 250 Base, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Headlights >> Lighting System (Ext) - Diagnostics - Introduction (1 Of 2) >> Lighting System >> Problem Symptoms Table [06/2014 - 08/2015] >> Problem Symptoms Table [06/2014 - 08/2015]

Problem Symptoms Table [06/2014 - 08/2015]

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 (FOR HID HEADLIGHT)

Symptom Suspected Area Link
One low beam headlight does not illuminate H-LP LH-LO fuse or H-LP RH-LO fuse -
Discharge headlight bulb Refer to ON-VEHICLE INSPECTION [04/2013 - 10/2016]
Headlight light control ECU sub-assembly Refer to REMOVAL [04/2013 - 10/2016]
Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Semiconductor pwr integration ECU Refer to INSPECTION [04/2013 - ]
Harness or connector -
Both left and right low beam headlights do not illuminate Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Low beam headlight circuit Refer to Low Beam Headlight Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
One high beam headlight does not illuminate Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Semiconductor pwr integration ECU Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Harness or connector -
Both left and right high beam headlights do not illuminate Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Headlight solenoid circuit Refer to Headlight Solenoid Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
"High Flash" (passing function) does not illuminate low beam headlights (high beam headlights are normal) Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
Discharge headlight bulb flickers Discharge headlight bulb Refer to ON-VEHICLE INSPECTION [04/2013 - 10/2016]
Harness or connector -
Headlight light control ECU sub-assembly Refer to REMOVAL [04/2013 - 10/2016]
Discharge headlight bulb is dark Discharge headlight bulb Refer to ON-VEHICLE INSPECTION [04/2013 - 10/2016]
Harness or connector -
Headlight light control ECU sub-assembly Refer to REMOVAL [04/2013 - 10/2016]
One front side marker light does not illuminate Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
Both left and right side marker lights do not illuminate Harness or connector -
Instrument panel junction block assembly Refer to REMOVAL [04/2013 - ]
HEADLIGHT (FOR LED HEADLIGHT)

Symptom Suspected Area Link
One low beam headlight does not illuminate H-LP LH-LO fuse or H-LP RH-LO fuse -
Light control LED ECU Refer to REMOVAL [04/2013 - 10/2016]
Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Semiconductor pwr integration ECU Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Harness or connector -
Both left and right low beam headlights do not illuminate Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Low beam headlight circuit Refer to Low Beam Headlight Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
One high beam headlight does not illuminate Light control LED ECU Refer to REMOVAL [04/2013 - 10/2016]
Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Semiconductor pwr integration ECU Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Harness or connector -
Both left and right high beam headlights do not illuminate Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
High beam headlight circuit Refer to High Beam Headlight Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
"High Flash" (passing function) does not illuminate low beam headlights (high beam headlights are normal) Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
One front side marker light does not illuminate Headlight unit Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
Both left and right side marker lights do not illuminate Harness or connector -
Instrument panel junction block assembly Refer to REMOVAL [04/2013 - ]
CLEARANCE LIGHT

Symptom Suspected Area Link
One clearance light does not illuminate Clearance light assembly Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
Both left and right clearance lights do not illuminate Harness or connector -
Instrument panel junction block assembly Refer to REMOVAL [04/2013 - ]
TAILLIGHT

Symptom Suspected Area Link
One side taillight and rear side marker light (rear combination light assembly) do not illuminate Rear combination light lens and body Refer to INSPECTION [04/2013 - 10/2016]
Rear combination light socket and wire sub-assembly Refer to INSPECTION [04/2013 - 10/2016]
Harness or connector -
One taillight (rear light assembly) does not illuminate Rear light lens and body Refer to INSPECTION [04/2013 - 10/2016]
Rear light socket and wire Refer to INSPECTION [04/2013 - 10/2016]
Harness or connector -
All of the lights (taillights, clearance lights, front side marker lights, rear side marker lights and license plate lights) do not illuminate (TAIL fuse is normal) Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Taillight relay circuit Refer to Taillight Relay Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
All of the lights (taillights, clearance lights, front side marker lights, rear side marker lights and license plate lights) do not illuminate (TAIL fuse breaks when replaced) License plate light assembly Refer to INSPECTION [04/2013 - 09/2020]
Rear combination light socket and wire sub-assembly Refer to INSPECTION [04/2013 - 10/2016]
Rear light socket and wire Refer to INSPECTION [04/2013 - 10/2016]
Clearance light assembly Refer to REMOVAL [04/2013 - 10/2016]
Headlight unit (for HID Headlight) Refer to REMOVAL [04/2013 - 10/2016]
Headlight unit (for LED Headlight) Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
LICENSE PLATE LIGHT

Symptom Suspected Area Link
One license plate light does not illuminate License plate light assembly Refer to INSPECTION [04/2013 - 09/2020]
Harness or connector -
Both left and right license plate lights do not illuminate Harness or connector -
STOP LIGHT

Symptom Suspected Area Link
One side stop light does not illuminate Rear combination light lens and body Refer to INSPECTION [04/2013 - 10/2016]
Rear combination light socket and wire sub-assembly Refer to INSPECTION [04/2013 - 10/2016]
Harness or connector -
Center stop light does not illuminate Center stop light assembly Refer to INSPECTION [04/2013 - ]
Radio setting condenser Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Harness or connector -
All of the stop lights do not illuminate STOP fuse -
Stop light switch assembly Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Semiconductor pwr integration ECU Refer to ON-VEHICLE INSPECTION [04/2013 - ]
Harness or connector -
FRONT FOG LIGHT (W/ FRONT FOG LIGHT)

Symptom Suspected Area Link
One front fog light does not illuminate Fog light assembly Refer to REMOVAL [06/2014 - 10/2016]
Harness or connector -
Both left and right front fog lights do not illuminate (taillights are normal) Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Front fog light circuit Refer to Front Fog Light Circuit [06/2014 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
BACK-UP LIGHT

Symptom Suspected Area Link
One back-up light does not illuminate Bulb -
Rear light socket and wire Refer to INSPECTION [04/2013 - 10/2016]
Harness or connector -
Both left and right back-up lights do not illuminate BKUP LP fuse -
Park/neutral position switch assembly (for A760H Automatic Transmission) Refer to INSPECTION [04/2013 - ]
Park/neutral position switch assembly (for A960E Automatic Transmission) Refer to INSPECTION [04/2013 - 08/2015]
Park/neutral position switch assembly (for AA81E Automatic Transmission) Refer to INSPECTION [04/2013 - ]
Instrument panel junction block assembly Refer to REMOVAL [04/2013 - ]
Harness or connector -
TURN SIGNAL LIGHT

Symptom Suspected Area Link
One turn signal light does not operate (except side turn signal lights) Bulb -
Headlight cord (for HID Headlight) Refer to INSPECTION [04/2013 - 10/2016]
Headlight cord (for LED Headlight) Refer to INSPECTION [04/2013 - 10/2016]
Headlight assembly (for HID Headlight) Refer to REMOVAL [04/2013 - 10/2016]
Headlight assembly (for LED Headlight) Refer to REMOVAL [04/2013 - 10/2016]
Rear combination light lens and body Refer to INSPECTION [04/2013 - 10/2016]
Rear combination light socket and wire sub-assembly Refer to INSPECTION [04/2013 - 10/2016]
Harness or connector -
One side turn signal light does not operate Side turn signal light assembly Refer to INSPECTION [04/2013 - 09/2020]
Outer rear view mirror assembly Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
Turn signal lights do not operate in one direction Turn signal switch circuit Refer to Turn Signal Switch Circuit [04/2013 - 10/2016]
Windshield wiper switch assembly Refer to REMOVAL [04/2013 - ]
Meter/gauge system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]
All turn signal lights do not operate Turn signal switch circuit Refer to Turn Signal Switch Circuit [04/2013 - 10/2016]
Windshield wiper switch assembly Refer to REMOVAL [04/2013 - ]
Combination meter assembly Refer to REMOVAL [04/2013 - 10/2016]
All turn signal lights do not flash at the correct speed Combination meter assembly Refer to REMOVAL [04/2013 - 10/2016]
HAZARD WARNING SIGNAL LIGHT

Symptom Suspected Area Link
Hazard warning signal lights do not operate Hazard warning switch circuit Refer to Hazard Warning Switch Circuit [04/2013 - 10/2016]
Combination meter assembly Refer to REMOVAL [04/2013 - 10/2016]
AUTOMATIC LIGHT CONTROL SYSTEM

Symptom Suspected Area Link
Automatic light control system does not operate Check DTCs Refer to DTC CHECK / CLEAR [04/2013 - 10/2016]
Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
LIGHT AUTO TURN-OFF SYSTEM

Symptom Suspected Area Link
Light auto turn-off system does not operate Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
IG signal circuit Refer to IG Signal Circuit [04/2013 - ]
Front door courtesy switch circuit Refer to Front Door Courtesy Switch Circuit [04/2013 - ]
Rear door courtesy switch circuit Refer to Rear Door Courtesy Switch Circuit [04/2013 - ]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
DAYTIME RUNNING LIGHT SYSTEM

Symptom Suspected Area Link
Daytime running light system does not operate (both left and right daytime running lights do not illuminate) CAN communication system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - 10/2016]
Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
IG signal circuit Refer to IG Signal Circuit [04/2013 - ]
Parking brake switch circuit Refer to Parking Brake Switch Circuit [04/2013 - 10/2016]
Daytime running light relay circuit Refer to Daytime Running Light Relay Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
One side daytime running light does not illuminate Clearance light assembly Refer to REMOVAL [04/2013 - 10/2016]
Harness or connector -
DOOR MIRROR FOOT LIGHT

Symptom Suspected Area Link
Both left and right door mirror foot lights do not illuminate CAN communication system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - 10/2016]
Power door lock control system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]
Wireless door lock control system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]
Smart access system with push-button start (for Entry Function) Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - 09/2022]
Door mirror foot light circuit Refer to Door Mirror Foot Light Circuit [04/2013 - 10/2016]
Door unlock detection switch circuit Refer to Door Unlock Detection Switch Circuit [04/2013 - ]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]
One door mirror foot light does not illuminate (w/ Power Mirror Control System) Door mirror foot light circuit Refer to Door Mirror Foot Light Circuit [04/2013 - 10/2016]
Outer mirror control ECU assembly Refer to REMOVAL [04/2013 - ]
One door mirror foot light does not illuminate (w/o Power Mirror Control System) Bulb -
Harness or connector -
Outer rear view mirror assembly Refer to REMOVAL [04/2013 - 10/2016]
WELCOME LIGHT ILLUMINATION CONTROL

Symptom Suspected Area Link
Welcome light illumination control does not operate Wireless door lock control system Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]
Headlight dimmer switch circuit Refer to Headlight Dimmer Switch Circuit [04/2013 - 10/2016]
Main body ECU (Multiplex network body ECU) Refer to REMOVAL [04/2013 - ]