Toyota Tundra Service Manual: Light Sensor Circuit Malfunction (B1244)

Toyota Tundra Service Manual / Vehicle Interior / Lighting / Lighting System / Light Sensor Circuit Malfunction (B1244)

DESCRIPTION

The automatic light control sensor detects ambient light. The sensor creates an electrical signal based on the amount of light detected, and sends the signal to the main body ECU (multiplex network body ECU). The main body ECU (multiplex network body ECU) turns on or off the headlights and taillights according to the signal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1244

Light Sensor Circuit Malfunction

Either of the following conditions is met:

Malfunction in automatic light control sensor
Open or short in automatic light control sensor circuit

Harness or connector
Automatic light control sensor
Main body ECU (multiplex network body ECU)

WIRING DIAGRAM

PROCEDURE

1.	CHECK FOR DTC

(a) Clear the DTCs.

Click here

(b) Turn the ignition switch to ON.

(d) Check for DTCs.

Click here

OK:

DTC B1244 is not output.

USE SIMULATION METHOD TO CHECK

2.	READ VALUE USING TECHSTREAM

(a) Using the Techstream, read the Data List.

Click here

(b) According to the display on the Techstream, read the Data List and check that the value of Light Sensor Illuminance changes while performing the following:

(1) Turn the light control switch to the AUTO position.

(2) Cover the automatic light control sensor with an opaque object.

(3) Slowly move the opaque object to uncover and then cover the automatic light control sensor.

Main Body

Tester Display	Measurement Item / Range	Normal Condition	Diagnostic Note
Light Sensor Illuminance	Light control sensor illuminance / 0 to 8191 lx	Value is output according to ambient light level	-

OK:

The value changes according to the amount the automatic light control sensor is covered.

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

3.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] - AUTOMATIC LIGHT CONTROL SENSOR)

(a) Disconnect the J165 main body ECU (multiplex network body ECU) connector.

(b) Disconnect the J176 automatic light control sensor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
J165-19 (CLTB) - J176-1 (CLTB)	Always	Below 1 Ω
J165-20 (CLTS) - J176-4 (CLTS)	Always	Below 1 Ω
J165-21 (CLTE) - J176-2 (CLTE)	Always	Below 1 Ω
J165-19 (CLTB) or J176-1 (CLTB) - Body ground	Always	10 kΩ or higher
J165-20 (CLTS) or J176-4 (CLTS) - Body ground	Always	10 kΩ or higher
J165-21 (CLTE) or J176-2 (CLTE) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

(a) Disconnect the J176 automatic light control sensor connector.

*a	Component with harness connected (Main Body ECU [Multiplex Network Body ECU])

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
J165-19 (CLTB) - J165-21 (CLTE)	Ignition switch off	Below 1 V
J165-19 (CLTB) - J165-21 (CLTE)	Ignition switch ON	11 to 14 V

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

5.	CHECK AUTOMATIC LIGHT CONTROL SENSOR

(a) Inspect the automatic light control sensor.

Click here

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPLACE AUTOMATIC LIGHT CONTROL SENSOR

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