Automatic Headlights: Overview Lexus ES XV30

DESCRIPTION & OPERATION

Operation

While the vehicle is being driven, the rear height control sensor detects the vehicle's posture that varies in accordance with the road conditions or driving conditions. The resultant signals are then output to the headlight beam level control ECU. Based on these signals from the sensor, the ECU assesses the vehicle's posture. If the front passenger seat is occupied, as determined by the ON/OFF signals from the occupant detection sensor that is built into the front passenger seat and the seat belt buckle switch, control is effected by making a correction to the vehicle posture information provided by the rear height control sensor. In addition, the skid control ECU sends the vehicle speed signal to the headlight beam level control ECU, allowing the ECU to determine the vehicle's driving conditions. This ECU controls the actuator so as to cancel out the changes in the light beams that are caused by these changes in the vehicle's posture and speed.

SYSTEM OPERATION CHECK

1. Trouble shooting of a headlight system complaint begins with verification of the customer problem. If problem occurs, go to step 3 . If problem does not occur, go to next step.
2. If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.
3. Check the multiplex communication system. Check that the DTC outputs. If a DTC outputs, see «MULTIPLEX COMMUNICATION SYSTEMS - ES 300»(ref-152050) article in COMMUNICATION DEVICES. If a DTC does not output go to the next step.
4. Perform a DTC check. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-152492-S29355374512003020700000) table.
5. Determine problem symptom. See «PROBLEM SYMPTOMS»(ref-152492-S09046876972003020700000) table. PROBLEM SYMPTOMS Symptom Suspected Area (1) Automatic Light Control System Automatic Light Control System Does Not Operate (2) Fog Light Front Fog Light Does Not Light Up With Light Control SW HEAD (Headlight Is Normal) (3) (4) (5) (9) Only One Front Fog Light Does Not Light Up (6) (9) Headlight & Taillight Only One Headlight Comes On (6) (7) (8) (9) Headlight (LO BEAM, DISCHARGE) Does Not Light Up (10) HI-Beam Does Not Light (All) (11) (12) (9) HI-Beam Does Not Light (One Side) (6) (9) Flash Does Not Light (11) (12) (9) Headlight Is Dark (6) (9) Only One Taillight Lights Up (6) (9) Taillight Does Not Light Up (Headlight Is Normal) (13) Taillight Does Not Light Up (Headlight Does Not Light) (14) (9) Rear Combination Light Does Not Light Up (6) (9) Headlight Does Not Come On With Engine Running & Light Control Switch Is In OFF (15) (12) (16) (17) (18) (9) Headlight Beam Level Control System Initial Set Control Function Does Not Operate (When Warning Light Lights Up) (19) Initial Set Control Function Does Not Operate (When Warning Light Goes Off) (20) Initial Set Control Function Operates, But Headlight Beam Level Control Does Not Operate (When Warning Light Lights Up) (21) Initial Set Control Function Operates, But Headlight Beam Level Control Does Not Operate (When Warning Light Goes Off) (22) Illuminated Entry System Room Lamp Assembly No. 1 Does Not Light Up (23) Room Lamp Assembly No. 1 Does Not Go Off (24) Courtesy Lamp Does Not Light Up (25) (26) (9) (27) Courtesy Lamp Does Not Go Off (26) (9) (25) (27) Light Auto Cut System Light Auto Turn Off System Does Not Operate (28) Headlight & Taillight Do Not Come On (18) (9) Headlight & Taillight Stay On (18) (9) Turn Signal & Hazard Warning System Hazard & Turn Do Not Light Up (29) (30) (31) (9) Hazard Warning Light Does Not Light Up (Turn Is Normal) (32) (9) Turn Signal Does Not Light Up (Hazard Is Normal) (33) (9) Turn Signal Does Not Light Up In One Direction (33) (9) Only One Bulb Does Not Light Up (6) (9) (1) Perform test procedures in order listed under suspected area. (2) See «DTC B1244: LIGHT SENSOR CIRCUIT MALFUNCTION»(ref-152492-S09818382692003020700000) under DIAGNOSTIC TESTS. (3) Check the FOG fuse. Located in the driver side junction block in the lower finish panel. (4) Check the FOG relay. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (5) Check the fog light switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (6) Check the bulb. (7) Check the HEAD LH fuse (LWR, UPR). (8) Check the HEAD RH fuse (LWR, UPR). (9) Check the wire harness. (10) See «TEST A: HEADLIGHT (LO BEAM, DISCHARGE) DOES NOT LIGHT UP»(ref-152492-S28217495702003020700000) under SYSTEM TESTS. (11) Check the headlight dimmer switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (12) Check the daytime running lights (DRL) relay. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (13) See «TEST B: TAILLIGHT DOES NOT LIGHT UP»(ref-152492-S21445332742003020700000) under SYSTEM TESTS. (14) Check the light control switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (15) Check the HEAD relay. (16) Check generator terminal L. (17) Check the parking brake switch. (18) Check the multiplex network body computer. See «MULTIPLEX COMMUNICATION SYSTEMS - ES 300»(ref-152050) article. (19) See «TEST C: INITIAL SET CONTROL FUNCTION DOES NOT OPERATE (WARNING LIGHT LIGHTS UP)»(ref-152492-S12243054452003020700000) under SYSTEM TESTS. (20) See «TEST DE: INITIAL SET CONTROL FUNCTION DOES NOT OPERATE (WARNING LIGHT GOES OFF)»(ref-152492-S26694071012003020700000) under SYSTEM TESTS. (21) See «TEST E: INITIAL SET CONTROL FUNCTION OPERATES, BUT HEADLIGHT AIMING DOES NOT OPERATE (WARNING LIGHT LIGHTS UP)»(ref-152492-S06081284862003020700000) under SYSTEM TESTS. (22) See «TEST F: INITIAL SET CONTROL FUNCTION OPERATES, BUT HEADLIGHT AIMING DOES NOT OPERATE (WARNING LIGHT GOES OFF)»(ref-152492-S40913996142003020700000) under SYSTEM TESTS. (23) See «TEST H: ROOM LAMP ASSEMBLY NO. 1 DOES NOT LIGHT UP»(ref-152492-S11051860192003021200000) under SYSTEM TESTS. (24) See «TEST I: ROOM LAMP ASSEMBLY DOES NOT GO OFF»(ref-152492-S25205997392003021200000) under SYSTEM TESTS. (25) Check courtesy lamp. (26) Check courtesy lamp switch. (27) Check driver side junction block assembly. (28) See «TEST G: LIGHT AUTO TURN OFF SYSTEM LIGHT DOES NOT OPERATE»(ref-152492-S01912990512003020700000) under SYSTEM TESTS. (29) Check the IG1 fuse. (30) Check the ignition switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (31) Check the turn signal flasher. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (32) Check the hazard warning switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article. (33) Check the turn signal switch. See «STEERING COLUMN SWITCHES - ES 300»(ref-152427) article.
6. Perform inspection of the terminals of ECU. See «TERMINALS OF ECU»(ref-152492-S25288353202003020700000) under COMPONENT TESTS.
7. After problem has been identified and repaired, confirm repairs. After repairs have been completed, confirm that problem has been eliminated. Operate system under same conditions recorded for original complaint. If problem is no longer present, repair has corrected problem. If problem is still present, further diagnosis and repair is required.

CONNECTOR IDENTIFICATION

For connector views (Scheme 1)

Scheme 1