Inspection Procedure

NOTE: First perform the communication function inspections in HOW TO PROCEED WITH TROUBLESHOOTING to confirm that there are no CAN communication malfunctions before troubleshooting this symptom.

READ VALUE USING TECHSTREAM (AUTOMATIC LIGHT CONTROL SENSOR)

Using the Techstream, read the Data List.

Main Body

DATA LIST

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

OK: Condition sign can be displayed.

OK: Go to step 4

NG: Go to Next Step

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AUTOMATIC LIGHT CONTROL SENSOR AND BODY GROUND)

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

Standard Resistance

RESISTANCE SPECIFICATION CHART

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

Fig 1: Identifying L12 ECU Connector And M2 Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

CHECK MAIN BODY ECU (CLTB VOLTAGE)

Disconnect the L12 ECU connector.
Measure the voltage according to the value (s) in the table below.

Standard Voltage

VOLTAGE SPECIFICATION

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

Fig 2: Identifying Main Body ECU Connector Terminals

NG: REPLACE MAIN BODY ECU

OK: REPLACE AUTOMATIC LIGHT CONTROL SENSOR (See AUTOMATIC LIGHT CONTROL SENSOR )

READ VALUE USING TECHSTREAM (HEADLIGHT DIMMER SWITCH)

Using the Techstream, read the Data List.

Combination Switch

DATA LIST

Tester Display	Measurement Item/Display	Normal Condition
Light Auto Switch	Headlight dimmer switch signal (AUTO position)/ON or OFF	ON: Headlight dimmer switch AUTO position OFF: Headlight dimmer switch OFF

OK: Condition sign can be displayed.

NG: REPLACE MAIN BODY ECU

OK: Go to Next Step

CHECK WINDSHIELD WIPER SWITCH (OPERATION)
1. Temporarily replace the windshield wiper switch with a new or normally functioning one (see REMOVAL ).
2. Check the windshield wiper switch operation.
OK: Windshield wiper switch operation is normal.

NG: REPLACE MAIN BODY ECU

OK: REPLACE WINDSHIELD WIPER SWITCH (See REMOVAL )