Lighting System (Diagnostics - Introduction) (Plug-In): Overview Toyota Prius Plug-in

SYSTEM DESCRIPTION

1. AUTOMATIC LIGHT CONTROL SYSTEM When the light control switch is in the AUTO position, the automatic light control system detects ambient light levels and controls the low beam headlights, parking lights, taillights, marker lights and license plate lights.
2. LIGHT AUTO TURN-OFF SYSTEM The light auto turn-off system is used to prevent the exterior lights from being accidentally left on (low beam headlights, high beam headlights, front fog lights, taillights, parking lights, license plate lights and marker lights). This system has the following functions. Function Outline Driver Door-linked Function The exterior lights automatically turn off when all of the following conditions are met: The power switch is turned from on (IG) to off. The light control switch is in the tail position. The driver door is opened. Delay Function The exterior lights automatically turn off after 30 seconds when all of the following conditions are met: The power switch is turned from on (IG) to off. The low beam headlights are on (light control switch is in the head or AUTO position). All doors are closed after any of the doors are opened. Door Control Transmitter-linked Function The exterior lights turn off immediately when the delay function is active and the following condition is met: The lock button on the key is pushed after all doors are locked. HINT: The delay function can not be cancelled when the remote A/C switch on the key is pressed to lock all of the doors.
3. DAYTIME RUNNING LIGHT SYSTEM (for Canada) The daytime running light system is designed to automatically illuminate the daytime running lights during the daytime to make the vehicle more visible to other vehicles. This system is controlled by the main body ECU (multiplex network body ECU) and daytime running light relay. The main body ECU (multiplex network body ECU) transmits a turn ON signal to the daytime running light relay, which illuminates the high beam headlights using duty control. This system is enabled when the following conditions are met: Power switch is on (IG). READY condition signal is received. Parking brake switch is off. Light control switch is in the off, tail or AUTO position (and the low beam headlights are not turned on via the automatic light control system).
4. DAYTIME RUNNING LIGHT SYSTEM (except Canada) The daytime running light system is designed to automatically illuminate the daytime running lights during the daytime to make the vehicle more visible to other vehicles. This system is controlled by the main body ECU (multiplex network body ECU) and daytime running light relay. The main body ECU (multiplex network body ECU) transmits a turn ON signal to the daytime running light relay, which illuminates the daytime running lights. This system is enabled when the following conditions are met: Power switch is on (IG). READY condition signal is received. Parking brake switch is off. Light control switch is in the tail or DRL position (w/o Automatic Light Control). Light control switch is in the tail or AUTO position (and the low beam headlights are not turned on via the automatic light control system) (w/ Automatic Light Control).
5. LED HEADLIGHT SYSTEM General LED headlights are used to provide efficient, maintenance free lighting. Compared to halogen or HID headlights, even if an LED headlight is used for a long time, the reduction of brightness over its lifetime is less. In addition, there is no possibility of an LED having an open circuit because of vibration. Function of Main Components Component Outline Light Control ECU Turns on the LEDs immediately when the light control switch is turned to the head position. Regulates the output current flowing into the LEDs at a specified level to prevent the light from getting brighter and dimmer due to voltage variation. Transmits fail signals to the main body ECU (multiplex network body ECU) when a malfunction occurs in the LED headlight system. Combination Meter Assembly Master Warning Light Flashes to inform the driver when the light control ECU detects malfunctions in this system. Multi-information Display Displays a warning message to inform the driver when the light control ECU detects a malfunction in this system. Main Body ECU (Multiplex Network Body ECU) Receives fail signals from the light control ECU when a malfunction occurs in the LED headlight system, and transmits the signals to the combination meter assembly. Stores Diagnostic Trouble Codes (DTCs) when the system malfunctions.

OPERATION CHECK

1. AUTOMATIC LIGHT CONTROL SYSTEM OPERATION CHECK Turn the power switch on (IG). Turn the light control switch to the AUTO position. Cover the automatic light control sensor. Check that the taillights and low beam headlights come on. Uncover the automatic light control sensor. Check that the low beam headlights and taillights go off.
2. LIGHT AUTO TURN-OFF SYSTEM OPERATION CHECK When only the taillights are on. Close the driver door. Turn the power switch on (IG). Turn the light control switch to the tail position. Turn the power switch off. Open the driver door. Check that the taillights go off immediately. When the low beam headlights are on. Close all of the doors. Turn the power switch on (IG). Turn the low beam headlights, high beam headlights or front fog lights on. Turn the power switch off. Open any door. Close all of the doors. Check that all of the lights go off after 30 seconds (delay function). HINT: Before the lights go off, if the lock button on the key is pushed after all of the doors are locked, all of the lights will go off immediately. But the lights will not go off immediately when the remote A/C switch on the key is pressed to lock all of the doors.
3. DAYTIME RUNNING LIGHT SYSTEM OPERATION CHECK Turn the light control switch to the tail position. Turn the power switch on (READY). Release the parking brake. Check that the daytime running lights come on.

See also:
• REMOVAL