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HOMESERVICE MANUALSTOYOTA2004CELICA GT, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 351 (LIGHTING SYSTEM - DIAGNOSIS)AUTOMATIC LIGHT CONTROL SYSTEM DOES NOT OPERATEINSPECTION PROCEDURE
2004 Toyota Celica GT, Standard

Inspection Procedure

2004 Toyota Celica GT, StandardSECTION Inspection Procedure
WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK LIGHT 
    1. Check that headlamp and taillight light up.

      NG: FLOW CHART (GO TO FLOW CHART OF HEADLAMP OR TAILLIGHT) 

      OK: Go to Next Step 

  2. READ VALUE OF HAND-HELD TESTER 
    1. Connect the hand-held tester to the DLC3.
    2. Turn the ignition switch ON and push the hand-held tester main SW ON.
    3. Select the item "AUTO LIGHT SW" in the DATA LIST and read its value displayed on the hand-held tester.

      OK: 

      • Light control SW AUTO --> ON 
      • Light control SW except AUTO --> OFF 

      NG: REPLACE HEADLAMP DIMMER SWITCH ASSY 

      OK: Go to Next Step 

  3. CHECK AUTOMATIC LIGHT CONTROL SENSOR 
    1. Check the continuity between terminal 3(+) and body ground as shown in Fig 2 .
      Fig 1: Checking Continuity Between Terminal 3 & Body Ground
      G01466659Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure voltage between terminals as shown in Fig 2 .
    3. Using an oscilloscope, check that signal waveform appears between terminals.

      Standard: 

      Fig 2: Automatic Light Control Sensor Chart
      G01466660Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: FLOW CHART (GO TO FLOW CHART OF HEADLAMP OR TAILLIGHT) 

      NG: Go to Next Step 

  4. CHECK HARNESS AND CONNECTOR (BETWEEN DRIVER SIDE J/B ASSY AND AUTOMATIC LIGHT CONTROL SENSOR) 
    1. Check that signal waveform appears between terminal B5 - 17 (CLTS) and body ground.

      Standard: Bar appears. 

      OK: CHECK AND REPLACE DRIVER SIDE JUNCTION BLOCK ASSY 

      NG: Go to Next Step 

  5. CHECK HARNESS AND CONNECTOR (BETWEEN DRIVER SIDE J/B ASSY AND AUTOMATIC LIGHT CONTROL SENSOR) 
    1. Measure voltage between terminal B5-15 (CLTB) and body ground.

      Standard: 10 - 14V 

      OK: CHECK AND REPLACE DRIVER SIDE JUNCTION BLOCK ASSY 

      NG: Go to Next Step 

  6. CHECK HARNESS AND CONNECTOR (BETWEEN DRIVER SIDE J/B ASSY AND AUTOMATIC LIGHT CONTROL SENSOR) 
    1. Check the continuity between terminal B5 - 16 (CLTE) of driver side J/B assy and 3 (CLTE) of automatic light control sensor.

      Standard: There is continuity. 

      OK: CHECK AND REPLACE DRIVER SIDE JUNCTION BLOCK ASSY 

      NG: REPLACE AUTOMATIC LIGHT CONTROL SENSOR 

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.