Problem Symptoms Table
WARNING: This page is about a different car, the 2007 Lexus SC 430. 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.
Headlight and taillight system
PROBLEM SYMPTOMS TABLE (HEADLIGHT AND TAILLIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| LO-beam headlight does not Illuminate | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Headlight relay circuit | HEADLIGHT RELAY CIRCUIT | |
| 3. Driver side junction block ECU | - | |
| HI-beam headlight does not illuminate | 1. Headlight (hi-beam) circuit | HEADLIGHT (HI-BEAM) CIRCUIT |
| 2. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Flash headlight does not illuminate | 1. Headlight (hi-beam) circuit | HEADLIGHT (HI-BEAM) CIRCUIT |
| 2. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Headlight is dark | 1. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT |
| 2. Driver side junction block ECU | - | |
| Headlight does not illuminate or has abnormal operation | 1. Power source circuit | POWER SOURCE CIRCUIT |
| 2. Headlight relay circuit | HEADLIGHT RELAY CIRCUIT | |
| 3. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 4. Driver side junction block ECU | - | |
| Taillight does not illuminate or has abnormal operation | 1. Taillight circuit | TAILLIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 4. Luggage room junction block ECU | - | |
| 5. Driver side junction block ECU | - | |
| Automatic light control system does not operate | 1. Automatic light control sensor circuit | DTC B1244 Light Sensor Circuit Malfunction |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Both left and right headlight do not illuminate | 1. Headlight (hi-beam) circuit | HEADLIGHT (HI-BEAM) CIRCUIT |
| 2. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Headlight beam level control system does not operate | 1. Headlight beam level control actuator circuit | DTC B2417 Headlight Beam Level Control Motor LH Malfunction; DTC B2418 Headlight Beam Level Control Motor RH Malfunction |
| 2. Height control sensor circuit | DTC B2416 Height Control Sensor Malfunction | |
| 3. AFS ECU power source circuit | AFS ECU Power Source Circuit | |
| 4. AFS ECU | - |
Stop light system
PROBLEM SYMPTOMS TABLE (STOP LIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| Stop light system does not operate | 1. Stop light switch circuit | STOP LIGHT SWITCH CIRCUIT |
| 2. Stop light circuit | STOP LIGHT CIRCUIT | |
| 3. Driver side junction block ECU | - | |
| High mounted stop light does not illuminate | 1. High mounted stop light circuit | HIGH MOUNTED STOP LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Driver side junction block ECU | - | |
| 4. Luggage room junction block ECU | - |
Fog light system
PROBLEM SYMPTOMS TABLE (FOG LIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| Fog light does not illuminate or has abnormal operation | 1. Front fog light circuit | FRONT FOG LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - |
Turn signal light system
PROBLEM SYMPTOMS TABLE (TURN SIGNAL LIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| Hazard warning light does not illuminate | 1. Hazard warning switch circuit | HAZARD WARNING SWITCH CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Turn signal light does not illuminate | 1. Turn signal light circuit | TURN SIGNAL LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - |
Illumination light system
PROBLEM SYMPTOMS TABLE (ILLUMINATION LIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| Each switch illumination light does not illuminate | 1. Illumination circuit | ILLUMINATION CIRCUIT |
| 2. Driver side junction block ECU | - | |
| Buckle illumination light does not illuminate | 1. Buckle illumination circuit | BUCKLE ILLUMINATION CIRCUIT |
| 2. Driver side junction block ECU or passenger side junction block ECU | - |
Interior light system
PROBLEM SYMPTOMS TABLE (INTERIOR LIGHT SYSTEM)
| Symptom | Suspected area | See |
|---|---|---|
| Door courtesy light does not illuminate | 1. Door courtesy light switch circuit | DOOR COURTESY SWITCH CIRCUIT |
| 2. Door courtesy light circuit | DOOR COURTESY LIGHT CIRCUIT | |
| 3. Driver side junction block ECU or passenger side junction block ECU | - | |
| Luggage compartment light does not illuminate | 1. Luggage room light circuit | LUGGAGE ROOM LIGHT CIRCUIT |
| 2. Luggage compartment door courtesy switch circuit | LUGGAGE COMPARTMENT DOOR COURTESY SWITCH CIRCUIT | |
| 3. Luggage room junction block ECU | - | |
| Interior light does not illuminate | 1. Room light circuit | ROOM LIGHT CIRCUIT |
| 2. Driver side junction block ECU | - | |
| AFS does not operate | 1. AFS ECU power source circuit | AFS ECU Power Source Circuit |
| 2. AFS ECU | - | |
| AFS OFF indicator light does not come on | 1. AFS OFF switch circuit | AFS OFF Switch Circuit |
| 2. Combination meter assembly | - | |
| 3. AFS ECU | - |
Other
PROBLEM SYMPTOMS TABLE (OTHER)
| Symptom | Suspected area | See |
|---|---|---|
| Back-up light does not illuminate | 1. Back-up light circuit | BACK-UP LIGHT CIRCUIT |
| 2. Driver side junction block ECU | - | |
| 3. Luggage room junction block ECU | - | |
| License plate light does not illuminate | 1. License plate light circuit | LICENSE PLATE LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Driver side junction block ECU | - | |
| 4. Luggage room junction block ECU | - | |
| Clearance light does not illuminate | 1. Clearance light circuit | CLEARANCE LIGHT CIRCUIT |
| 2. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 3. Power source circuit | POWER SOURCE CIRCUIT | |
| 4. Front light ECU (Front controller) | - | |
| 5. Passenger side junction block ECU | - | |
| Front side marker light does not illuminate | 1. Front side marker light circuit | FRONT SIDE MARKER LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Front light ECU (Front controller) | - | |
| 4. Driver side junction block ECU | - | |
| Rear side marker light does not illuminate | 1. Rear side marker light circuit | REAR SIDE MARKER LIGHT CIRCUIT |
| 2. Power source circuit | POWER SOURCE CIRCUIT | |
| 3. Luggage room junction block ECU | - | |
| 4. Driver side junction block ECU | - | |
| Light auto turn off system does not operate (Headlight is normal) | 1. Headlight (hi-beam) circuit | HEADLIGHT (HI-BEAM) CIRCUIT |
| 2. Light control switch circuit | LIGHT CONTROL SWITCH CIRCUIT | |
| 3. Driver side junction block ECU | - |