Toyota Tacoma (2015-2018) Service Manual: Light Sensor Circuit Malfunction (B1244)

Toyota Tacoma (2015-2018) Service Manual / Lighting / Lighting System / Light Sensor Circuit Malfunction (B1244)

DESCRIPTION

This DTC is output when a failure of the automatic light control sensor circuit is detected.

DTC Code	DTC Detection Condition	Trouble Area
B1244	When either condition below is met: Malfunction of light sensor Open or short of light sensor circuit	Automatic light control sensor Harness or connector Main body ECU (Multiplex network body ECU)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

If the main body ECU (multiplex network body ECU) is replaced, refer to Registration (See page ).*1

*1: w/ Smart Key System

PROCEDURE

1.	CHECK FOR DTC

(a) Clear the DTC (See page (b) Recheck for DTC (See page ). ).

(b) Recheck for DTC (See page OK: ).

OK:

DTC B1244 is not output.

USE SIMULATION METHOD TO CHECK

2.	READ VALUE USING TECHSTREAM (LIGHT SENSOR ILLUMINANCE)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: Body Electrical / Main Body / Data List.

(e) According to the display on the Techstream, read the Data List.

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:

Output illuminance is as shown in table above.

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

3.	CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (LIGHT CONTROL SENSOR VOLTAGE)

(a) Disconnect the ECU connector.

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

Standard voltage:

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

Text in Illustration

*a	Component without harness connected (Main Body ECU (Multiplex Network Body ECU))

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

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

(a) Disconnect the M6 main body ECU (multiplex network body ECU) connector.

(b) Disconnect the A37 automatic light control sensor connector.

Standard resistance:

Tester Connection	Condition	Specified Condition
M6-19 (CLTB) - A37-1 (CLTB)	Always	Below 1 Ω
M6-20 (CLTS) - A37-4 (CLTS)
M6-21 (CLTE) - A37-2 (CLTE)
M6-19 (CLTB) - Body ground	Always	10 kΩ or higher
M6-20 (CLTS) - Body ground
M6-21 (CLTE) - Body ground

REPLACE AUTOMATIC LIGHT CONTROL SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

Terminals Of Ecu

TERMINALS OF ECU 1. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Text in Illustration *1 Main Body ECU (Multiplex Network Body ECU) - - (a ...

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DATA LIST / ACTIVE TEST 1. DATA LIST HINT: Using the Techstream to read the Data List allows values or states of switches, sensors, actuators and other items to be read without removing any parts ...

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