LIGHTING SYSTEM PROBLEM SYMPTOMS TABLE
Tech Tips
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.
| Symptom | Suspected Area | See page |
|---|---|---|
| One low beam headlight does not illuminate (for ALPHARD). | H-LP LL fuse or H-LP RL fuse | - |
| Bulb | - | |
| Harness or connector | - | |
| Light control ECU (Headlight light control ECU sub-assembly) | ||
| Headlight unit | ||
| One low beam headlight does not illuminate (for VELLFIRE). | H-LP LL fuse or H-LP RL fuse | - |
| Bulb | - | |
| Harness or connector | - | |
| Light control ECU (Headlight light control ECU sub-assembly) | ||
| Headlight unit | ||
| Both left and right low beam headlights do not illuminate. | Light control switch circuit | |
| Headlight relay circuit | ||
| Main body ECU | ||
| One high beam headlight does not illuminate. | H-LP LH fuse or H-LP RH fuse | - |
| Bulb | - | |
| Harness or connector | - | |
| Both left and right high beam headlights do not illuminate. | Light control switch circuit | |
| High beam Headlight circuit | ||
| Main body ECU | ||
| "High Flash" (passing function) headlight does not illuminate (high beam headlights are normal). | Light control switch circuit | |
| Main body ECU |
| Symptom | Suspected Area | See page |
|---|---|---|
| One front clearance light does not illuminate. | Bulb | - |
| Harness or connector | - | |
| One rear taillight does not illuminate (for ALPHARD). | Bulb | - |
| Harness or connector | - | |
| One rear taillight does not illuminate (for VELLFIRE). | Harness or connector | - |
| Rear combination light assembly | ||
| Rear light assembly | ||
| One license plate light does not illuminate. | Bulb | - |
| Harness or connector | - | |
| All of lights do not illuminate. | Light control switch circuit | |
| Taillight relay circuit | ||
| Main body ECU |
| Symptom | Suspected Area | See page |
|---|---|---|
| One side stop light does not illuminate (for ALPHARD). | STP RL fuse or STP RR fuse | - |
| Harness or connector | - | |
| Rear combination light assembly | ||
| One side stop light does not illuminate (for VELLFIRE). | STP RL fuse or STP RR fuse | - |
| Harness or connector | - | |
| Rear combination light assembly | ||
| High-mounted stop light does not illuminate. | STP HI MT fuse | - |
| High-mounted stop light assembly | ||
| Harness or connector | - | |
| All of lights do not illuminate. | STOP fuse | - |
| Stop light switch | ||
| Stop light control relay | ||
| Harness or connector | - |
| Symptom | Suspected Area | See page |
|---|---|---|
| One side front fog light does not illuminate. | Bulb | - |
| Harness or connector | - | |
| Both left and right front fog lights do not illuminate (taillight is normal). | FOG fuse | - |
| Light control switch circuit | ||
| Front fog light circuit | ||
| Main body ECU |
| Symptom | Suspected Area | See page |
|---|---|---|
| One back-up light does not illuminate. | Bulb | - |
| Harness or connector | - | |
| Both left and right back-up lights do not illuminate. | GAUGE NO. 2 fuse | - |
| Park/Neutral position switch (for A/T U660E) | ||
| Park/Neutral position switch (for A/T U241E) | ||
| Park/Neutral position switch (for CVT) | ||
| Harness or connector | - |
| Symptom | Suspected Area | See page |
|---|---|---|
| Side turn signal light does not operate. | Side turn signal light assembly | |
| Harness or connector | - | |
| One turn signal light does not operate (except side turn signal lights). | Bulb | - |
| Harness or connector | - | |
| Turn signal lights do not operate in one direction. | Headlight dimmer switch assembly (Turn signal light switch) | |
| Turn signal flasher assembly | ||
| Harness or connector | - | |
| All turn signal lights do not operate. | TRN-HAZ fuse | - |
| RH ECU-IG fuse | - | |
| Headlight dimmer switch assembly (Turn signal light switch) | ||
| Turn signal flasher assembly | ||
| Harness or connector | - | |
| All turn signal lights do not flash at the correct speed. | Bulb | - |
| Turn signal flasher assembly | ||
| Harness or connector | - |
| Symptom | Suspected Area | See page |
|---|---|---|
| Hazard warning lights do not operate. | TRN-HAZ fuse | - |
| RH ECU-IG fuse | - | |
| Hazard warning switch | ||
| Turn signal flasher assembly | ||
| Harness or connector | - |
| Symptom | Suspected Area | See page |
|---|---|---|
| Automatic light control does not operate normally. | Check DTCs | |
| Light control switch circuit | ||
| IG signal circuit | ||
| Main body ECU |
| Symptom | Suspected Area | See page |
|---|---|---|
| Light turn-off control does not operate normally. | Light control switch circuit | |
| Door courtesy switch circuit | ||
| IG signal circuit | ||
| Main body ECU |
| Symptom | Suspected Area | See page |
|---|---|---|
| AFS does not operate. | Check DTCs | |
| AFS ECU power source circuit | ||
| AFS ECU | ||
| AFS control can not be cancelled using AFS OFF switch. | AFS OFF switch circuit | |
| AFS ECU | ||
| Initialization can not be performed. | Check DTCs | |
| LVL terminal circuit | ||
| AFS ECU | ||
| AFS OFF indicator light does not come on when turning the engine switch on (IG). | AFS ECU | |
| Combination meter |
Note
-
Initialize the AFS ECU after the vehicle height changes due to replacement of the suspension or after performing such operations as removal and reinstallation or replacement of the rear height control sensor sub-assembly LH.
-
When the AFS ECU is replaced, the initialization is also necessary.
| Symptom | Suspected Area | See page |
|---|---|---|
| Headlight beam level control does not operate (for ALPHARD). | Check the FAIL-SAFE function | |
| Headlight beam level control actuator circuit | ||
| Headlight signal circuit | ||
| Headlight leveling ECU power source circuit | ||
| Combination meter assembly | ||
| Headlight leveling motor (headlight unit) | ||
| Headlight leveling ECU assembly | ||
| Headlight beam level control does not operate (for VELLFIRE). | Check the FAIL-SAFE function | |
| Headlight beam level control actuator circuit | ||
| Headlight signal circuit | ||
| Headlight leveling ECU power source circuit | ||
| Combination meter assembly | ||
| Headlight leveling motor (headlight unit) | ||
| Headlight leveling ECU assembly | ||
| Headlight beam level control system indicator light does not come on when turning the engine switch on (IG). | Indicator light circuit | |
| Headlight leveling ECU power source circuit | ||
| Headlight leveling ECU assembly | ||
| Combination meter assembly | ||
| Initialization can not be performed. | LVL terminal circuit | |
| Headlight leveling ECU assembly |
Note
-
Initialize the headlight leveling ECU assembly after the vehicle height changes due to replacement of the suspension or after performing such operations as removal and reinstallation or replacement of the rear height control sensor sub-assembly.
-
When the headlight leveling ECU assembly is replaced, the initialization is also necessary.
| Symptom | Suspected Area | See page |
|---|---|---|
| Inner rear view mirror assembly indicator light does not come on when engine switch is turned from off to on (IG). | Inner rear view mirror assembly | |
| Harness or connector | - | |
| Inner rear view mirror assembly indicator light remains on or flashes when inner rear view mirror assembly AUTO switch is pressed. | Inner rear view mirror assembly | |
| Automatic high beam indicator light does not come on when automatic high beam system is in standby mode (automatic light control system operates normally). | Combination meter assembly | |
| Main body ECU | ||
| Automatic high beam indicator light does not come on when automatic high beam system is in standby mode (automatic light control system does not operate). | Check DTCs | |
| Headlight (HI-BEAM) circuit | ||
| Light control switch circuit | ||
| Check automatic light control system operation | ||
| Check Data List (Auto H Beam STS) | ||
| Inner rear view mirror assembly | ||
| AFS ECU | ||
| Main body ECU | ||
| "CHECK AHB SYSTEM" is displayed on the multi-information display. | Check DTCs | |
| Main body ECU | ||
| Combination meter assembly |
Tech Tips
-
Camera detection malfunctions can be detected using the intelligent tester. Under the following conditions, if the camera built into the inner rear view mirror assembly cannot detect other vehicles or lights correctly, it will stop automatic high beam control and turn off the automatic high beam indicator light:
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When the front windshield is not clear (ice, snow or frost on the glass).
-
When the front windshield is dirty (sand, mud, water stains or bugs are on the glass).
-
Aiming misalignment of the camera can be detected using the intelligent tester. If the camera aiming is misaligned, check the following conditions:
-
Check if the vehicle is inclined.
-
Check if the windshield glass is installed correctly.
-
Check if the inner rear view mirror assembly is installed correctly.
-
Check if there is deformation of the camera or stay of the inner rear view mirror assembly.