DTC    B1244    Light Sensor Circuit Malfunction

for Preparation Click here


DESCRIPTION

The automatic light control sensor detects ambient light, converts it into an electrical signal, and outputs it to the main body ECU. The main body ECU turns on or off the headlights and taillights according to the signal.

DTC No.
DTC Detection Condition
Trouble Area
B1244
  1. Malfunction in automatic light control sensor
  2. Open or short in automatic light control sensor circuit
  1. Automatic light control sensor
  2. Harness or connector
  3. Main body ECU

WIRING DIAGRAM


E177341E01


INSPECTION PROCEDURE

1.CHECK FOR DTC

  1. Clear the DTC (Click here).

  1. Recheck for DTC (Click here).

    OK:
    DTC B1244 is not output.



NG
Go to step 2
OK

USE SIMULATION METHOD TO CHECK (Click here)  

2.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Body / Main Body / Data List.

  1. According to the display on the tester, read the Data List.

    Main Body 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Illumination Rate Info
    		Illumination rate
    Min.: 0 ms.
    Max.: 99.99 ms.
    		Actual illumination rate is displayed
    		-

    OK:
    Output illumination is as shown in table above.



NG
Go to step 3
OK

REPLACE MAIN BODY ECU (Click here)  

3.INSPECT AUTOMATIC LIGHT CONTROL SENSOR (SYSTEM VOLTAGE)


    E107010E17

  1. Disconnect the T1 automatic light control sensor connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    T1-3 (CLTB) - T1-6 (CLTE)
    		Ignition switch ON
    		11 to 14 V
    Ignition switch off
    		Below 1 V

Text in Illustration 
*1
Front view of wire harness connector
(to Automatic Light Control Sensor)

  1. Reconnect the automatic light control sensor connector.



NG
Go to step 4
OK

REPLACE AUTOMATIC LIGHT CONTROL SENSOR (Click here)  

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


    E174461E02

  1. Disconnect the D42 main body ECU connector.

  1. Disconnect the T1 automatic light control sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D42-20 (CLTB) - T1-3 (CLTB)
    		Always
    		Below 1 Ω
    D42-20 (CLTB) - Body ground
    		Always
    		10 kΩ or higher
    D42-21 (CLTS) - T1-4 (CLTS)
    		Always
    		Below 1 Ω
    D42-21 (CLTS) - Body ground
    		Always
    		10 kΩ or higher
    D42-22 (CLTE) - T1-6 (CLTE)
    		Always
    		Below 1 Ω
    D42-22 (CLTE) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Main Body ECU)
    *2
    		Front view of wire harness connector
    (to Automatic Light Control Sensor)

  1. Reconnect the automatic light control sensor connector.

  1. Reconnect the main body ECU connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MAIN BODY ECU (Click here)