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Problem Symptoms Table

WARNING: This page is about a different car, the 2004 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

LIGHTING SYSTEM: 

PROBLEM SYMPTOMS TABLE - LIGHTING SYSTEM

Symptom Suspected Area
Headlight does not come on. (Low beam)
  1. Light control switch circuit
  2. Headlight relay circuit
  3. Combination switch
  4. Body ECU (Main)
Headlight system does not operate. (HI beam or Flash)
  1. Headlight dimmer switch circuit
  2. Light control switch circuit
  3. Combination switch
  4. Body ECU (Main)
Automatic light control system does not operate.
  1. Light control sensor circuit
  2. Light control sensor
  3. Body ECU (Main)
Taillight system does not come on.
  1. Taillight relay circuit
  2. Taillight circuit
  3. Light control switch circuit
  4. Combination switch
  5. Body ECU (Sub)
  6. Body ECU (Main)
Stop light system does not come on.
  1. Stop light switch
  2. Stop light circuit
  3. Body ECU (Sub)

HAZARD WARNING SYSTEM: 

PROBLEM SYMPTOMS TABLE - HAZARD WARNING SYSTEM

Symptom Suspected Area
Hazard warning light does not come on.
  1. Hazard switch
  2. Flasher relay

ILLUMINATION LIGHT SYSTEM: 

PROBLEM SYMPTOMS TABLE - ILLUMINATION LIGHT SYSTEM

Symptom Suspected Area
Illumination light does not come on.
  1. Power source circuit (Body ECU (Sub))
  2. Power source circuit (Body ECU (Main))
  3. Illumination circuit (Body ECU (Main) control)
  4. Illumination circuit (Body ECU (Sub) control)
  5. Body ECU (Sub)
  6. Body ECU (Main)
Brightness does not change even when rheostat is turned on. (All)
  1. Light control rheostat
  2. Body ECU (Main)
Door courtesy light does not come on.
  1. Door courtesy switch circuit
  2. Body ECU (Main)

DRIVER SEAT BELT SYSTEM: 

PROBLEM SYMPTOMS TABLE - DRIVER SEAT BELT SYSTEM

Symptom Suspected Area
Driver seat belt warning does not come on.
  1. Driver buckle switch circuit
  2. Combination meter
  3. Body ECU (Main)

POWER DOOR LOCK CONTROL SYSTEM: 

PROBLEM SYMPTOMS TABLE - POWER DOOR LOCK CONTROL SYSTEM

Symptom Suspect Area
All the doors can not be locked or unlocked.
  1. Power source circuit (Body ECU (Main))
  2. Body ECU (Main)
Driver side door lock does not operate.
  1. Door lock motor circuit
  2. Body ECU (Main)
Door key related function cannot be done.
  1. Door key lock and unlock switch circuit
  2. Door courtesy switch circuit
  3. Body ECU (Main)
Key confinement prevention function does not operate.
  1. Door courtesy switch circuit
  2. Door unlock detection switch circuit
  3. Body ECU (Main)

POWER SEAT CONTROL SYSTEM: 

PROBLEM SYMPTOMS TABLE - POWER SEAT CONTROL SYSTEM

Symptom Suspect Area
Driving position memory system does not operate.
  1. Memory switch circuit (w/memory)
  2. Power seat control ECU
  3. Body ECU (Main)

WIRELESS DOOR LOCK CONTROL SYSTEM: 

PROBLEM SYMPTOMS TABLE - WIRELESS DOOR LOCK CONTROL SYSTEM

Symptom Suspect Area
Wireless door lock does not operate.
  1. Wireless door lock control circuit
  2. Wireless door lock tuner
  3. Body ECU (Main)
Wireless door lock buzzer does not operate.
  1. Wireless door lock buzzer circuit
  2. Body ECU (Main)

REAR WIPER SYSTEM: 

PROBLEM SYMPTOMS TABLE - REAR WIPER SYSTEM

Symptom Suspect Area
Rear wiper system does not operate.
  1. Door courtesy switch circuit (back door)
  2. Power source circuit (Body ECU (Sub))
  3. Rear wiper switch circuit
  4. Rear wiper motor circuit
  5. Body ECU (Sub)
Rear washer linked function does not operate.
  1. Rear wiper switch circuit
  2. Body ECU (Sub)
Vehicle speed switching function does not operate.
  1. Door courtesy switch circuit (back door)
  2. Speed signal circuit
  3. Body ECU (Sub)
  4. Body ECU (Main)
Reverse linked function does not operate.
  1. Door courtesy switch circuit (back door)
  2. Reverce signal circuit
  3. Front wiper position circuit
  4. Body ECU (Sub)

OTHERS: 

PROBLEM SYMPTOMS TABLE - OTHER INDICATORS

Symptom Suspect Area
Key unlock warning system does not operate.
  1. Key unlock warning switch circuit
  2. Key unlock warning switch
  3. Combination meter
  4. Body ECU (Main)
Parking brake indicator does not come on.
  1. Parking brake switch circuit
  2. Combination meter
  3. Body ECU (Main)
Open door warning light does not come on.
  1. Open door warning light circuit
  2. Door courtesy switch
  3. Combination meter
  4. Body ECU (Main)
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