Automatic Headlights: Other Lexus ES XV30

AUTOMATIC HEADLIGHT BEAM LEVEL CONTROL

The automatic headlight beam level control system regulates the orientation of the reflectors of the headlights in relation to the posture of the vehicle that has been detected by sensors. (Scheme 33) Thus, it is a system that maintains the headlight beams to a constant level while the vehicle is being driven.

The headlight beam level control ECU assessed the vehicle's posture through the signals from the rear height control sensor. There is another piece of information that is used for assessing the vehicle's posture. It also determines whether or not the front passenger seat is occupied. This is accomplished by way of the ON/OFF signal of the occupant detection sensor, which is built into the front passenger seat and the seat belt buckle switch.

The headlight beam level control ECU has the initial value of the rear height control sensor stored in it's memory. Therefore, if a repair that alters the output value of the rear height control sensor has been performed (such as removal and reinstallation of the rear height control sensor or the suspension), it is necessary to initialize the sensor and adjust the beams.

Scheme 33

Actuator

Based on the signals received from the headlight beam level control ECU, each actuator moves the reflector in the headlight to vary it's beam. This actuator uses a step motor to precisely regulate the angle of the reflector.

Fail-Safe Function

The headlight beam level control ECU operates in the fail-safe mode if an abnormal condition such as those listed below has been detected and illuminates the automatic headlight leveling system warning light in the instrument panel.

1. Actuator - Holds the beam at the position of the actuator when the abnormality (open or short) has been detected.
2. Rear Height Control Sensor - Returns the beam to the actuator's initial set position if a signal level abnormality has been detected higher than the initial set position. Holds the beam at the position of the actuator when a signal level abnormality has been detected, if the abnormality has been detected lower than the initial set position.
3. Headlight Beam Level Control ECU - Holds the beam at position of the actuator when the abnormality (abnormal processing of the CPU) has been detected.

Headlight Beam Level Control ECU

Based on the signals that are transmitted by height control sensors, the occupant detection sensor and the skid control ECU, this ECU detects the amount of variance of the vehicle posture. Based on the detected value, this ECU outputs control signal to the actuator. The headlight beam level control ECU provides initial set control and fail-safe function.

Occupant Detection Sensor & Seat Belt Buckle Switch

The ON/OFF signals of the occupant detection sensor that is built into the front passenger seat and the seat belt buckle switch determine whether the front passenger seat is occupied. The signals are then transmitted to the headlight beam level control ECU. The occupant detection sensor is shared with the seat belt warning system.

Rear Height Control Sensor

The rear height control sensor detects the amount of variance of the vehicle height while the vehicle is being driven and output this amount in the form of signal to the headlight beam level control ECU. This sensor is located in the rear right suspension.

Skid Control ECU

The skid control ECU outputs the wheel speeds to the headlight beam level control ECU. The wheel speeds are calculated based on the signals which are received from the speed sensors which are part of the ABS.

DAYTIME RUNNING LIGHTS (DRL)

This system, which is directly connected to the high-beam headlights, is designed to automatically activate them in the daytime in order to keep the vehicle highly visible to other vehicles. (Scheme 34)

Scheme 34

HIGH INTENSITY DISCHARGE (HID) HEADLIGHT

Note. The HID headlight system consists of metal halide bulbs and a light control ECU.

Metal Halide Bulb

The metal halide bulb contains xenon gas, mercury and metal halide. (Scheme 35)

Operation

1. When high voltage (approximately 20,000 volts) is applied to the electrodes of the metal halide bulb, the xenon gas in the bulb emits light.
2. As the temperature in the bulb rises, the mercury evaporates and causes arcs to be discharged.
3. As the temperature in the bulb rises even further, the metal halide in the mercury arc separates into metal atoms and iodine atoms.
4. The separated metal atoms discharge light, which causes the bulb to emit light.

Scheme 35

Light Control ECU

The light control ECU is an electronic control unit which is necessary for illuminating the metal halide bulb. A light control ECU is located under each headlight unit. This ECU provides the functions listed below

1. Generates the high voltage (approximately 20,000 volts) which is applied to the electrodes of the bulbs to enable the HID headlights to start to illuminate.
2. Optimally controls the amperage and voltage in order to quickly provide an optimal amount of light immediately after the bulbs have been turned ON and to enable the bulbs to continue to illuminate in a stable manner.
3. A fail-safe function is provided as a countermeasure against the high voltage that is generated in case that a problem occurs in the headlight system.

The light control ECU executes the fail-safe actions listed below in accordance with the item that has been detected.

1. Detection of Abnormal Input Voltage - If the voltage that is input to the light control ECU deviates from the operating voltage (9-16 volts), the ECU stops illuminating the headlights and resumes illuminating the headlights once the voltage reverts to the operating voltage range. However, if the input voltage decreases after the headlights have illuminated, the headlights will remain illuminated until the bulbs are extinguished.
2. Detection of Abnormal Output (Open Circuit or Short Circuit) or Flashing Bulb - If an abnormal condition (open or short circuit) occurs in the voltage that is output by the light control ECU, or if the bulb flashes, the ECU stops illuminating the headlights and will maintain this state until the power is reinstated (by tuning the headlight control switch from OFF to ON).
3. Detection of Bulb Open - If a bulb is not inserted in it's socket, the ECU stops generating high voltage until the bulb is inserted correctly and the power is reinstated (by turning the headlight control switch from OFF to ON or turning the ignition switch from OFF to ON).

ILLUMINATED ENTRY SYSTEM

When a door is unlocked through a key operation or transmitter operation, or if a door is opened or closed, the illuminated entry system turns ON the interior light and the ignition key illumination. If the ignition switch is turned to the ACC or ON position or if all doors are locked during the 15 seconds in which these lights are ON, they will immediately turn OFF. This system is controlled by the Body ECU.

LIGHT AUTO TURN-OFF SYSTEM

When the headlights and taillights are illuminated through the operation of the light control switch or the activation of the automatic light control system, if the ignition switch is turned OFF and all the doors are closed, this system continues to illuminate the headlights and taillights for approximately 30 seconds and then turns OFF the headlights. However, the headlights and taillights are turned OFF immediately when the vehicle is locked by the wireless door lock remote control. This system is controlled by the Body ECU.

HEADLIGHT AIM

Note. When the vehicle height is changed, for example, remove and install the height control sensor, or replace the suspension, etc., initialize the sensor, then adjust the optical axis.

Note. Numbers in parenthesis refer to numbers in illustration.

1. Place the vehicle in the following conditions: The area around the headlight is not deformed. The vehicle is parked on a level surface. Tire inflation pressure is in the specified value. A driver is in the driver's seat and the vehicle is in a state ready for driving (with a full tank). The vehicle has been bounced several times.
2. Check the headlight aiming: Prepare a thick white paper. Stand the paper perpendicular to the ground at the position 9.84 ft (3 meters) away from the headlights. Ensure that the center line of the vehicle and the paper face forms a 90 degree angle. (Scheme 36) Draw a horizontal line (H line) on the paper, showing where the headlights should strike. (4) Draw a vertical line (V line) to where the center line of the vehicle is to be. (5) Draw a horizontal line (by connecting both low beam center marks) to where the headlights should strike (right and left H lines). (6) NOTE: The left and right H line of the low beam is 0.4 degrees below the horizontal line (H line) of the light axis. Take appropriate measures to prevent any influence of other lights. (7) Start the engine. Turn the headlights ON. Check that the headlights properly strike the position. If not, adjust the lights in the vertical direction.
3. When adjusting the headlight aim in the horizontal direction: High Beam: Using adjusting bolt A, adjust the headlight aim to within the specified range. (Scheme 37) Low Beam: On vehicles with the discharge headlights, use adjusting bolt B to adjust the headlight to be within the specified range. On vehicles with the halogen headlights, use adjusting bolt A to adjust the headlight air to be within the specified range.

Scheme 36

Scheme 37

FOG LIGHT AIM

The fog light aim can be adjusted by moving the aiming screw in the vertical direction. (Scheme 38) The optical aim moves upward when turning a screwdriver clockwise, while it moves downward when turning a screwdriver counter clockwise.

Scheme 38

PRE-CHECK

1. Use the hand-held tester. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-152492-S06161017972003021200000) .
2. Clear the DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-152492-S40827924452003021200000) .
3. Connect the OBD II scan tool or hand-held tester to the DLC3. Turn the ignition switch ON. According to the display on the tester, read the DATA LIST. See «DATA LIST»(ref-152492-S13430254922003021200000) table. DATA LIST Item Measurement Item/Display (Range) Normal Condition LUGG COURTSY SW Luggage Compartment Door's Courtesy SW Signal/ON Or OFF ON: Luggage Door Is Open, OFF: Luggage Door Is Closed D DOR CTY SW Driver's Door Courtesy SW Signal/ON Or OFF ON: Driver's Door Is Open, OFF: Driver's Door Is Closed P DOR CTY SW Passenger's Door Courtesy SW Signal/ON Or OFF ON: Passenger's Door Is Open, OFF: Passenger's Door Is Close RR DOR CTY SW Rear Door Courtesy SW Signal/ON Or OFF ON: Either Right Or Left Rear Door Is Open, OFF: Both The Right & Left Doors & Closed DIMMER SE Dimmer SW Signal/ON Or OFF ON: Dimmer SW Is On (High Beam) Or High Flasher SW Is On, OFF: Dimmer SW Is OFF (Low Beam) & High Flasher SW Is Off (1) HIGH FLASHER SW High Flasher SW Signal/ON Or OFF ON: High Flasher SW Is On, OFF: High Flasher SW Is Off (1) AUTO LIGHT SW Auto Light SW Signal/ON Or OFF ON: Light Control SW Is In Auto Position, OFF: Light Control SW Is In Except Auto Position (2) HEAD LIGHT SW Headlight SW Signal/ON Or OFF ON: Light Control SW Is In HEAD Position, OFF: Light Control SW Is In Except HEAD Position (2) TAIL LIGHT SW Taillight SW Signal/ON Or OFF ON: Light Control SW Is In TAIL Or HEAD Position, OFF: Light Control SW Is In OFF Or AUTO Position (2) ACC SW ACC SW Signal/ON Or OFF ON: IG Key Is In ACC, ON Or START Position, OFF: IG Key Is In OFF Position IG SW IG SW Signal/ON Or OFF ON: IG Key Is In ON Or START Position, OFF: IG Key Is In OFF Or ACC Position (1) See «DIMMER & HIGH FLASHER SWITCH POSITIONS»(ref-152492-S22805506682003021200000) . (2) See «TAILLIGHT, HEADLIGHT & AUTO LIGHT SWITCH POSITIONS»(ref-152492-S34530248392003021200000) . DIMMER & HIGH FLASHER SWITCH POSITIONS Switch Position Dimmer Switch High Flasher SW OFF OFF OFF HIGH BEAM ON OFF HIGH FLASHER ON ON TAILLIGHT, HEADLIGHT & AUTO LIGHT SWITCH POSITIONS Switch Position Taillight Switch (Headlight Switch) Auto Light Switch DRL OFF OFF (OFF) OFF TAIL ON (ON) OFF HEAD OFF (ON) OFF AUTO OFF (OFF) ON
4. Connect the OBD II scan tool or hand-held tester to the DLC3. Turn the ignition switch ON. According to the display on the tester, perform the ACTIVE TEST. See «ACTIVE TEST»(ref-152492-S07566730562003021200000) table. ACTIVE TEST Item Test Details HAZARD Turns Hazard Light Flasher Relay ON/OFF TRUNK/BDOR OPEN Drive The Luggage Door Lock Motor ON/OFF DRL RLY Test Details: Turns DRL Relay ON/OFF, Vehicle Condition: IG SW Is ON, Engine Is Stopped & Light Control SW Is In OFF Position HEAD LIGHT Turns Head Light Relay ON/OFF TAIL LIGHT Turns Taillight Relay ON/OFF ILLUMI OUTPUT Test Details: Turns Interior Light & Key Illumination ON/OFF, Vehicle Condition: Interior Light SW Is In Door Position STEP LIGHT Turns Step Light ON/OFF DOOR LOCK Drive The Door Lock Motor At All Doors LOCK/UNLOCK
5. Check the illuminated entry system operation: The light that is lit in the illuminated entry system is the key cylinder light and the room light. Turn the ignition switch to OFF, close all the doors and set the driver door in the lock condition. Unlock the driver door and open any of the other doors and check that the room light goes on. Close the door and check that the room light goes off in about 15 seconds. Turn the ignition switch to ON and open and close any other of the doors. Check that the room light immediately goes off. Turn the ignition switch OFF. Open and close any of the doors to light the room light. Before the room light goes off in about 15 seconds, turn the ignition switch to ON. Check that the room light goes off immediately. Turn the ignition switch to OFF. Open and close any of the doors to light the room light. Before the light goes off in about 15 seconds, lock the driver door. Check that the light goes off immediately.
6. Check the battery saver operation: Remove the ignition key and close all the doors. Open the driver door to light the room light and leave it as it is. Check that the light goes off in about 20 minutes. After the room light goes off, close the driver door. Open the passenger door or either of the rear doors to light the room light. Open the driver door within 20 minutes. Check that the room light goes off in about 20 minutes from the time when the driver door is opened. Close all the doors With the ignition key being inserted, open any one of the doors to light the room light. In this condition, remove the ignition key. Check that the room light goes off in about 20 minutes. Close all the doors. Open any one of the doors to light the room light. Insert the ignition key within 20 minutes. Check that the room light goes off in about 20 minutes from the time when the ignition key is inserted.
7. Check the fail-safe function: The headlight leveling control ECU performs the fail-safe when detecting the following troubles. At this the warning indicator light on the instrument panel lights up. See «HEADLIGHT LEVELING CONTROL ECU FAIL-SAFE FUNCTION»(ref-152492-S42107807922003021200000) table. HEADLIGHT LEVELING CONTROL ECU FAIL-SAFE FUNCTION Trouble Area Condition Headlight Speed Sensor Open Circuit Or Short Circuit Vehicle Speed Sensor Speed Signal Error Height Control Sensor Signal Level Error Headlight Leveling Actuator High Voltage, Motor Is Locked Or Temperature Malfunction Headlight Leveling Control ECU Watchdog Detection Check the fail-safe function of the light control computer. See «LIGHT CONTROL COMPUTER FAIL-SAFE FUNCTION»(ref-152492-S14789856042003021200000) table. LIGHT CONTROL COMPUTER FAIL-SAFE FUNCTION Condition Content Output Open Lighting Of Headlight Stops, Condition Is Maintained Until Power Is Turned ON Again (Headlight Dimmer Switch OFF To ON) Short Between Output Terminals Lighting Of Headlight Stops Within 1 Second & Condition Is Maintained Until Power Is Turned ON Again (Headlight Dimmer Switch OFF To ON) Leakage Between Output Terminal & Body Ground Lighting Of Headlight Stops, Condition Is Maintained Until Power Is Tuned ON Again (Headlight Dimmer Switch OFF To ON) Low Lamp Voltage Lighting Of Headlight Stops, Condition Is Maintained Until Power Is Turned ON Again (Headlight Dimmer Switch OFF To ON) Height Lamp Voltage Lighting Of Headlight Stops, Condition Is Maintained Until Power Is Turned ON Again (Headlight Dimmer Switch OFF To ON) Bulb Flushing Condition Is Maintained More Than 60 Seconds; Lighting Of Headlight Stops, Condition Is Maintained Until Power Is Turned ON Again (Headlight Dimmer Switch OFF To ON) High Input Voltage As Soon As Voltage Comes Within Range Of Operation Voltage (9-16 Volts), It Lights Up Again Low Input Voltage When Voltage Is 9.5-7.5 volts, Lighting Condition Is Maintained Until Possible Voltage (Below 6 Volts) To Keep Lighting & Lighting Of Headlight Stops; As Soon As Voltage Becomes Within Range Of Operation Voltage (More Than 9 Volts), It Lights Up Again

SYSTEM TESTS

SYMPTOM INDEX

DAYTIME RUNNING LIGHT RELAYS NO. 1 & NO. 2

For daytime running light relays No. 1 and No. 2, see STEERING COLUMN SWITCHES - ES 300 article.

FOG LAMP RELAY

For fog lamp relay component test, see STEERING COLUMN SWITCHES - ES 300 article.

Glove Box Lamp

Check that there is continuity between terminals when the switch is operated. The standard results are when the shaft is pressed (ON) there is no continuity and when the shaft is not pressed (OFF) there is continuity.

Luggage Compartment Door Courtesy Lamp Switch

Inspect that there is continuity between terminal No. 2 and body ground when the switch is operated. See CONNECTOR IDENTIFICATION . The standard results are no continuity when the shaft is pressed (ON) and continuity when the shaft is not pressed (OFF).

TERMINALS OF ECU

Note. Perform test procedures in order listed.

Multiplex Network Body Computer

For multiplex network body computer connector view, see CONNECTOR IDENTIFICATION. Inspect the multiplex network body computer voltage and continuity. (Scheme 39) If the value is not within standard range, some defects on the vehicle side are suspect. Inspect the fuse, wiring harness and connector.

Scheme 39

1. For headlight beam level control ECU connector view, see «CONNECTOR IDENTIFICATION»(ref-152492-S00924433792003020700000). Inspect the headlight beam level control ECU voltage and continuity. (Scheme 40)
2. Check the signal waveform. Using an oscilloscope, check the signal waveform between the headlight leveling ECU terminals SPDR - GND. (Scheme 41) See «HEADLIGHT BEAM LEVEL CONTROL ECU SIGNAL WAVEFORM 1»(ref-152492-S02834769142003021400000) table. HEADLIGHT BEAM LEVEL CONTROL ECU SIGNAL WAVEFORM 1 Item Specification Tool Setting 5 V/DIV, 2 ms/DIV Condition Drive At About 30 Km/h
3. Check the signal waveform. Using an oscilloscope, check the signal waveform between the headlight leveling ECU terminals RH+, RHT, RH- RHE - RHG, LH+, LHT, LH- and LHE - LHG. see scheme 20 See «HEADLIGHT BEAM LEVEL CONTROL ECU SIGNAL WAVEFORM 2»(ref-152492-S16283944052003021400000) table. HEADLIGHT BEAM LEVEL CONTROL ECU SIGNAL WAVEFORM 2 Item Specification Tool Setting 5 V/DIV, 10 ms/DIV Condition Light Control Switch HEAD Or DRL System Is ON & Engine Running, When Keeping & Bouncing The Vehicle
4. If the value is not within the standard range, some defects on the vehicle side are suspect. Inspect the fuse, wiring harness and connector.

Scheme 40

Scheme 41

Driver Door ECU (Power Window Regulator Master Switch)

See CONNECTOR IDENTIFICATION . See INSPECTING DRIVER DOOR ECU table.

INSPECTING DRIVER DOOR ECU\

Passenger Door ECU (Power Window Regulator Switch)

See CONNECTOR IDENTIFICATION . See INSPECTING PASSENGER DOOR ECU table.

INSPECTING PASSENGER DOOR ECU

TAIL LAMP RELAY

For tail lamp relay test, see STEERING COLUMN SWITCHES - ES 300 article.

HEIGHT CONTROL SENSOR

Note. Initialize the height control sensor as the following procedure. After work that could change the vehicle height such as height control sensor removal and installation and suspension replacement, initialize the sensor, then adjust the optical axis would be needed before adjusting the headlight aiming. Reduce the fuel amount to 2.64 gal. (10 L). Unload luggage from a vehicle as many as possible. Using SST, connect terminals No. 12 and 16 of DLC 3 with IG switch ON. Turn the headlight dimmer switch OFF to HEAD to OFF. Check that the indicator on the combination meter blinks twice and disconnect the SST from DLC3. If the indicator does not blink, work from step 1 .