Inspection Procedure

1. Clear the DTC (see DTC CHECK/CLEAR  ).
2. Check for DTC (see DTC CHECK/CLEAR  ).

   OK: DTC B1244 output does not occur. 

NG: Go to step 2 

OK: USE SIMULATION METHOD TO CHECK  (See HOW TO PROCEED WITH TROUBLESHOOTING )

1. Using the intelligent tester or Techstream, read the Data List
   1. Intelligent tester

      MAIN BODY 

      INTELLIGENT TESTER MAIN BODY REFERENCE CHART
      
      

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      ILLUMINATE RAT	Condition of automatic light control sensor/0 to 235600 Ix	Condition value will be displayed	-

   2. Techstream

      Main Body 

      TECHSTREAM MAIN BODY REFERENCE CHART
      
      

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      Illumination Rate Info	Condition of automatic light control sensor/0 to 235600 Ix	Condition value will be displayed	-

      OK: Output illuminance is as shown in table above. 

NG: Go to step 3 

OK: REPLACE MAIN BODY ECU 

1. Measure the voltage according to the value (s) in the table below.

   Standard voltage 

   TESTER CONNECTION SPECIFIED CONDITION REFERENCE CHART
   
   

   Tester Connection	Switch Condition	Specified Condition
   L12-20 (CLTB) - L12-18 (CLTE)	Power switch ON (IG)	11 to 14 V

   Fig 1: Identifying L12 Main Body ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE MAIN BODY ECU 

OK: Go to next step 

1. Disconnect the L12 ECU connector.
2. Disconnect the M2 sensor connector.
3. Measure the resistance according to the value (s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION REFERENCE CHART
   
   

   Tester Connection	Condition	Specified Condition
   L12-20 (CLTB) - M2-6 (CLTB)	Always	Below 1 Ω
   L12-19 (CLTS) - M2-5 (CLTS)
   L12-18 (CLTE) - M2-3 (CLTE)
   L12-20 (CLTB) - Body ground	Always	10 kΩ or higher
   L12-19 (CLTS) - Body ground
   L12-18 (CLTE) - Body ground

   Fig 2: Identifying L12 ECU And M2 Sensor Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: REPLACE AUTOMATIC LIGHT CONTROL SENSOR  (See ON-VEHICLE INSPECTION  )