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Home >> Lexus >> 2001 >> LX 470 >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 93 (Multiplex Control Systems) >> Diagnostic Tests >> DTC B1244/44: Automatic Light Control Sensor Circuit Malfunction >> Diagnostic Procedure (With Scan Tool)
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Diagnostic Procedure (With Scan Tool)

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to DLC3 located under left side of instrument panel. See Figure. Turn ignition switch and scan tool main switch to ON position. Using scan tool, monitor automatic light control function with light control switch in AUTO position. While observing illumination rate change on scan tool, expose automatic light control sensor to light, then cover it completely to imitate darkness. See Figure. The rate of change between "OFF-TO-ON" and "ON-TO-OFF" should be between 0.8-22.0 milliseconds. If rate of change is within 0.8-22.0 milliseconds, go to next step. If rate of change is not within 0.8-22.0 milliseconds, adjust and retest. See AUTOMATIC HEADLIGHTS - AVALON article under HEADLIGHTS in ACCESSORIES & EQUIPMENT.
  2. Using DVOM, check for an open or short circuit condition of following circuits between body control ECU 25-pin electrical harness connector B5 and Black automatic light control sensor 4-pin connector A28. See Figure and Figure .
    • Light Green wire between body control ECU 25-pin electrical harness connector B5 terminal No. 8 and Black automatic light control sensor 4-pin connector A28 terminal No. 4.
    • Yellow/Black wire between body control ECU 25-pin electrical harness connector B5 terminal No. 7 and Black automatic light control sensor 4-pin connector A28 terminal No. 3.
    • Blue wire between body control ECU 25-pin electrical harness connector B5 terminal No. 20 and Black automatic light control sensor 4-pin connector A28 terminal No. 1.
    If an open or short circuit condition is present on any of the listed circuits, repair wiring harness as necessary and retest system. See HEADLIGHTS in SYSTEM WIRING DIAGRAMS article. If all circuits are okay, diagnose body control ECU and retest system. See BODY CONTROL SYSTEM under TROUBLE SHOOTING under BODY CONTROL SYSTEMS - AVALON article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.
  3. After repairs have been made, perform confirmation test. See CONFIRMATION TEST  under SELF-DIAGNOSTIC SYSTEM.
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