Note
Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.
If the headlight control computer assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the headlight control computer assembly LH.
Click here
Inspect the fuses and relays related to this system before inspecting the suspected areas below.
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 | Link |
|---|---|---|
| Left low beam headlight does not illuminate | Headlight Unit LH | |
| Headlight unit assembly LH (w/o Canister Pump Module) | ||
| Headlight control computer assembly LH | ||
| Right low beam headlight does not illuminate | Headlight Unit RH | |
| Headlight unit assembly RH (w/o Canister Pump Module) | ||
| Headlight control computer assembly RH | ||
| Both left and right low beam headlights do not illuminate | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | ||
| Left high beam headlight does not illuminate | Headlight Unit LH | |
| Headlight unit assembly LH (w/o Canister Pump Module) | ||
| Headlight control computer assembly LH | ||
| Right high beam headlight does not illuminate | Headlight Unit RH | |
| Headlight unit assembly RH (w/o Canister Pump Module) | ||
| Headlight control computer assembly RH | ||
| Both left and right high beam headlights do not illuminate | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | ||
| High flash (passing function) does not operate (high beam headlights are normal) | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) | ||
| Left low beam headlight and high beam headlight do not illuminate | Power source circuit | |
| Headlight control computer assembly LH | ||
| Right low beam headlight and high beam headlight do not illuminate | Power source circuit | |
| Headlight control computer assembly RH | ||
| Left clearance light does not illuminate | Headlight Unit LH | |
| Headlight unit assembly LH (w/o Canister Pump Module) | ||
| Headlight control computer assembly LH | ||
| Clearance Light/Daytime Running Light Circuit | ||
| Right clearance light does not illuminate | Headlight Unit RH | |
| Headlight unit assembly RH (w/o Canister Pump Module) | ||
| Headlight control computer assembly RH | ||
| Clearance Light/Daytime Running Light Circuit | ||
| Both left and right clearance lights do not illuminate | Headlight dimmer switch circuit | |
| Main body ECU (Multiplex network body ECU) |
| Symptom | Suspected Area | Link |
|---|---|---|
| One license plate light does notilluminate | License plate light assembly | |
| Harness or connector | - | |
| Both left and right license plate lights do not illuminate | Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| Taillight does not illuminate (rear combination light). | Rear combination light assembly | |
| Harness or connector | - | |
| Taillight does not illuminate (rear light). | Rear light assembly | |
| Harness or connector | - | |
| All lights do not illuminate. | Headlight dimmer switch circuit | |
| Taillight relay circuit | ||
| Harness or connector | - | |
| No. 2 integration relay | ||
| Main body ECU (Multiplex network body ECU) |
| Symptom | Suspected Area | Link |
|---|---|---|
| Stop light on one side does not illuminate. | Rear combination light assembly | |
| Harness or connector | - | |
| Center stop light does not illuminate. | Center stop light assembly | |
| Harness or connector | - | |
| All lights do not operate. | Stop light switch assembly | |
| Stop light circuit | ||
| Harness or connector | - | |
| No. 2 integration relay |
| Symptom | Suspected Area | Link |
|---|---|---|
| Back-up light on one side does not illuminate. | Rear light assembly | |
| Harness or connector | - | |
| Both left and right license plate lights do not illuminate. | Park/neutral position switch assembly | |
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| Headlight dimmer switch assembly (turn signal light switch) does not function properly. | Windshield wiper switch assembly | |
| Headlight dimmer switch assembly | ||
| Spiral cable with sensor sub-assembly (steering angle sensor) | ||
| Harness or connector | - | |
| No turn signal lights operate. | Turn signal switch circuit | |
| Windshield wiper switch assembly | ||
| Combination meter assembly | ||
| One of the turn signal lights does not operate. | Meter/gauge system |
| Symptom | Suspected Area | Link |
|---|---|---|
| Hazard warning lights do not operate (turn signal lights are normal). | Hazard warning switch circuit | |
| Combination meter assembly | ||
| Harness or connector | - |
| Symptom | Suspected Area | Link |
|---|---|---|
| Automatic light control system does not operate. | Headlight dimmer switch circuit | |
| IG signal circuit | ||
| Main body ECU (Multiplex network body ECU) |
| Symptom | Suspected Area | Link |
|---|---|---|
| Light auto turn-off system does not operate. | Headlight dimmer switch circuit | |
| Door courtesy switch circuit | ||
| IG signal circuit | ||
| Main body ECU (Multiplex network body ECU) |
| Symptom | Suspected Area | Link |
|---|---|---|
| Left daytime running light does not illuminate | Clearance Light/Daytime Running Light Circuit | |
| Headlight control computer assembly LH | ||
| Right daytime running light does not illuminate | Clearance Light/Daytime Running Light Circuit | |
| Headlight control computer assembly RH | ||
| Both left and right daytime running lights do not illuminate | CAN communication system (for LHD) | |
| CAN communication system (for RHD) | ||
| Headlight dimmer switch circuit | ||
| Main body ECU (Multiplex network body ECU) |