Automatic Light Control Function does not Operate: Procedure

1. Using the Techstream, read the Data List.
   MAIN BODY
   
   

   Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
   Illumination Rate Info	Illuminance detected by automatic light control sensor/0 to 235600 lx	Illuminance value displayed	-

   OK

   Illuminance value is displayed normally.

NG → See step   5 

OK: Go to next step 

1. Using the Techstream, read the Data List.
   MAIN BODY
   
   

   Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
   Light Auto SW	Headlight dimmer switch (AUTO) signal/ ON or OFF	ON: Headlight dimmer switch (AUTO) on OFF: Headlight dimmer switch OFF	-

   OK

   When the headlight dimmer switch operation is performed, the result will be the same as above.

NG → See step   3 

OK → REPLACE MAIN BODY ECU 

1. Remove the headlight dimmer switch. Refer to REMOVAL .
   Fig 1: Inspecting Headlight Dimmer Switch

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   19 (A) - 12 (EL)	Headlight dimmer switch (Light control switch) AUTO	Below 1 Ω
   	Headlight dimmer switch (Light control switch) off	10 kΩ or higher

NG → See step   7 

OK: Go to next step 

1. Disconnect the E14 switch connector.
   Fig 2: Identifying E14 Switch And E1 ECU Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the E1 ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E14-19 (A) - E1-21 (A)	Always	Below 1 Ω
   E14-12 (EL) - Body ground
   E14-19 (A) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE MAIN BODY ECU 

Fig 3: Identifying E2 ECU And F9 Sensor Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the E2 ECU connector.
2. Disconnect the F9 sensor connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E2-20 (CLTB) - F9-6 (CLTB)	Always	Below 1 Ω
   E2-19 (CLTS) - F9-5 (CLTS)
   E2-18 (CLTE) - F9-3 (CLTE)
   E2-20 (CLTB) - Body ground	Always	10 kΩ or higher
   E2-19 (CLTS) - Body ground
   E2-18 (CLTE) - Body ground

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

Fig 4: Checking Main Body ECU (CLTB Voltage)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the E2 ECU connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   20 (CLTB) - Body ground	Engine switch on (IG)	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   8