Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VKHH
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 -           ]
Title: LIGHTING (EXT): LIGHTING SYSTEM: B1244; Light Sensor Circuit Malfunction; 2016 - 2020 MY Sienna [12/2015 -        ]

DTC

B1244

Light Sensor Circuit Malfunction

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 Detecting Condition

Trouble Area

B1244
  • Malfunction in automatic light control sensor
  • Open or short in automatic light control sensor circuit
  • Automatic light control sensor
  • Harness or connector
  • Main body ECU

WIRING DIAGRAM

PROCEDURE

1.

READ VALUE USING TECHSTREAM (ILLUMINATION RATE INFO)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

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

(e) Read the display on the Techstream.

Main Body

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Illumination Rate Info

Illumination rate information/0 ms to 99.99 ms

Value is output according to ambient light levels

-

OK:

Normal condition listed above is displayed.

OK

REPLACE MAIN BODY ECU

NG

2.

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

(a) Disconnect the D144 automatic light control sensor connector.

(b) Disconnect the D13 main body ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D13-22 (CLTE) - D144-3 (CLTE)

Always

Below 1 Ω

D13-21 (CLTS) - D144-5 (CLTS)

Always

Below 1 Ω

D13-20 (CLTB) - D144-6 (CLTB)

Always

Below 1 Ω

D13-22 (CLTE) or D144-3 (CLTE) - Body ground

Always

10 kΩ or higher

D13-21 (CLTS) or D144-5 (CLTS) - Body ground

Always

10 kΩ or higher

D13-20 (CLTB) or D144-6 (CLTB) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

INSPECT MAIN BODY ECU

(a) Reconnect the D13 main body ECU connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

D13-20 (CLTB) - D13-22 (CLTE)

Ignition switch off

Below 1 V

Ignition switch ON

11 to 14 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

D13-22 (CLTE) - Body ground

Always

Below 1 Ω

Text in Illustration

*a

Component with harness connected

(Main Body ECU)
NG

REPLACE MAIN BODY ECU

OK

4.

INSPECT AUTOMATIC LIGHT CONTROL SENSOR

(a) Reconnect the automatic light control sensor connector.

Text in Illustration

*a

Component with harness connected

(Automatic Light Control Sensor)

(b) Connect an oscilloscope to the automatic light control sensor connector.

(c) Check the waveform.

OK:

Tester Connection

Tool Setting

Switch Condition

Specified Condition

D144-3 (CLTE) - D144-5 (CLTS)

5 V/DIV., 5 ms./DIV.

Ignition switch ON, light control switch in AUTO position

Correct waveform is as shown

HINT:

If the ambient light becomes brighter, width A becomes narrower.
OK

REPLACE MAIN BODY ECU

NG

REPLACE AUTOMATIC LIGHT CONTROL SENSOR