Problem Symptoms Table
WARNING: This page is about a different car, the 2009 Toyota Prius. 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 the problem symptom. 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.
- Inspect the fuses and relays related to this system before inspecting the suspected areas below.
Headlight and taillight system
HEADLIGHT AND TAILLIGHT SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Low beam does not turn on (one side) | 1. Bulb | - |
| 2. Wire harness | - | |
| 3. Light control computer (HID) | - | |
| Low beam does not turn on (both sides) | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Headlight relay circuit | HEADLIGHT RELAY CIRCUIT | |
| 3. Main body ECU | - | |
| High beam does not turn on (one side) | 1. Bulb | - |
| 2. Wire harness | - | |
| High beam does not turn on (both sides) | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Headlight relay circuit | HEADLIGHT RELAY CIRCUIT | |
| 3. DRL relay circuit (w/ DRL) | DAYTIME RUNNING LIGHT RELAY CIRCUIT | |
| 4. Main body ECU | - | |
| FLASH does not turn on (Low beam and high beam are normal) | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Main body ECU | - | |
| Headlight is dim | 1. Bulb | - |
| 2. Wire harness | - | |
| Taillight does not turn on (all) | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. TAIL relay circuit | TAILLIGHT RELAY CIRCUIT | |
| 3. Main body ECU | - | |
| Taillight does not turn on (one) | 1. Bulb | - |
| 2. Wire harness | - | |
| Daytime running light system does not operate | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Headlight relay circuit | HEADLIGHT RELAY CIRCUIT | |
| 3. DRL relay circuit | DAYTIME RUNNING LIGHT RELAY CIRCUIT | |
| 4. Parking brake switch circuit | BRAKE CONTROL WARNING LIGHT DOES NOT COME ON | |
| 5. Main body ECU | - |
Automatic light control system
AUTOMATIC LIGHT CONTROL SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Automatic light control system does not operate | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Automatic light control sensor circuit | AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT | |
| 3. Main body ECU | - |
Light auto turn off system
LIGHT AUTO TURN OFF SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Light auto turn off system does not operate | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Door courtesy switch circuit | DOOR COURTESY SWITCH CIRCUIT | |
| 4. Main body ECU | - |
Fog light system
FOG LIGHT SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Fog light does not turn on (one side) | 1. Bulb | - |
| 2. Wire harness | - | |
| Fog light does not turn on (both sides) | 1. Headlight dimmer switch | HEADLIGHT DIMMER SWITCH |
| 2. Wire harness | - | |
| 3. Main body ECU | - |
Turn signal light and hazard warning system
TURN SIGNAL LIGHT AND HAZARD WARNING SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Hazard and turn signal do not turn on | 1. Turn signal flasher relay | TURN SIGNAL FLASHER ASSEMBLY |
| 2. Wire harness | - | |
| 3. Driver side junction block | - | |
| Hazard warning light does not turn on (Turn is normal) | 1. Hazard warning | HAZARD WARNING SWITCH |
| 2. Wire harness | - | |
| 3. Driver side junction block | - | |
| Turn signal does not turn on (Hazard is normal) | 1. Headlight dimmer switch | HEADLIGHT DIMMER SWITCH |
| 2. Wire harness | - | |
| 3. Driver side junction block | - | |
| Turn signal does not turn on in one direction | 1. Bulb | - |
| 2. Wire harness | - | |
| 3. Driver side junction block | - |
Stop light system
STOP LIGHT SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Stop light does not turn on (one) | 1. Bulb | - |
| 2. Wire harness | - | |
| Stop light does not turn on (all) | 1. Stop light switch | STOP LIGHT SWITCH |
| 2. Stop light control relay assembly (w/ Stop Light Control Relay Assembly) | STOP LIGHT CONTROL RELAY | |
| 3. Wire harness | - |
Illuminated entry system
ILLUMINATED ENTRY SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Illuminated entry system controlled by the multiplex network body ECU does not operate | 1. Power source circuit | POWER SOURCE CIRCUIT |
| 2. Door lock position circuit | DOOR LOCK POSITION CIRCUIT | |
| 3. Door courtesy switch circuit | DOOR COURTESY SWITCH CIRCUIT | |
| 4. Main Body ECU | - |
Headlight beam level control system
HEADLIGHT BEAM LEVEL CONTROL SYSTEM PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Headlight beam level control system does not operate (warning light turns on) | 1. Headlight beam level control ECU power source circuit | HEADLIGHT BEAM LEVEL CONTROL ECU |
| 2. Height control sensor circuit | HEIGHT CONTROL SENSOR CIRCUIT | |
| 3. Headlight beam level control ECU | - | |
| Headlight beam level control system does not operate (warning light turns off) | 1. Headlight signal circuit | HEIGHT CONTROL SENSOR CIRCUIT |
| 2. Headlight beam level control actuator circuit | HEADLIGHT BEAM LEVEL CONTROL ECU | |
| 3. Warning light circuit | WARNING LIGHT CIRCUIT | |
| 4. Headlight beam level control ECU | - | |
| Headlight beam level control system cannot be canceled during low speed driving (driving condition cannot be determined) | 1. Vehicle speed signal circuit | VEHICLE SPEED SIGNAL CIRCUIT |
| 2. Headlight beam level control ECU | - |
Others
OTHERS PROBLEM SYMPTOM
| Symptom | Suspected area | Refer To |
|---|---|---|
| Vanity light does not turn on | 1. Bulb | - |
| 2. Wire harness | - | |
| Back up light does not turn on | 1. Bulb | - |
| 2. Back/up relay | - | |
| 3. Wire harness | - | |
| Luggage room light does not turn on | 1. Bulb | - |
| 2. Wire harness | - | |
| Courtesy light does not turn on | 1. Bulb | - |
| 2. Door courtesy light switch | REAR DOOR COURTESY SWITCH | |
| 3. Wire harness | - | |
| 4. Body ECU | - |