Lexus NX: Light Sensor Circuit Malfunction (B1244)
DESCRIPTION
The automatic light control sensor detects ambient light, converts it into an electrical signal and outputs it to the main body ECU (multiplex network body ECU). The main body ECU (multiplex network body ECU) turns the headlights and taillights on or off according to the signal.
The main body ECU (multiplex network body ECU) outputs DTC B1244.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| B1244 | Light Sensor Circuit Malfunction |
|
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WIRING DIAGRAM
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CAUTION / NOTICE / HINT
NOTICE:
- Recognition code registration is necessary when replacing the main body ECU (multiplex network body ECU).
-
If the main body ECU (multiplex network body ECU) is replaced, refer to Registration.
Click here
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PROCEDURE
| 1. | CLEAR DTC |
(a) Clear the DTCs.
Click here
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| 2. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
| DTC B1244 output does not occur | .gif) | USE SIMULATION METHOD TO CHECK |
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| 3. | READ VALUE USING TECHSTREAM (LIGHT SENSOR ILLUMINANCE) |
(a) Using the Techstream, read the Data List.
Click here
| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Light Sensor Illuminance | Light control sensor illuminance | 0 to 17600 lx | Value is output according to ambient light level | - |
| Tester Display |
|---|
| Light Sensor Illuminance |
OK:
The display is as specified in the normal condition column.
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
|
| 4. | CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AUTOMATIC LIGHT CONTROL SENSOR) |
(a) Disconnect the I48 main body ECU (multiplex network body ECU) connector.
(b) Disconnect the J6 automatic light control sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I48-21 (CLTE) - J6-2 (CLTE) | Always | Below 1 Ω |
| I48-19 (CLTB) - J6-1 (CLTB) | Always | Below 1 Ω |
| I48-20 (CLTS) - J6-4 (CLTS) | Always | Below 1 Ω |
| I48-21 (CLTE) - Body ground | Always | 10 kΩ or higher |
| I48-19 (CLTB) - Body ground | Always | 10 kΩ or higher |
| I48-20 (CLTS) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| (a) Remove the instrument panel junction block assembly and main body ECU (multiplex network body ECU) as a unit with the connectors still connected. Click here |
|
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(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| I48-19 (CLTB) - I48-21 (CLTE) | Power switch off | Below 1 V |
| Power switch on (IG) | 11 to 14 V |
| NG | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
|
| 6. | CHECK AUTOMATIC LIGHT CONTROL SENSOR |
(a) Check the automatic light control sensor.
Click here
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE AUTOMATIC LIGHT CONTROL SENSOR |
READ NEXT:
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DESCRIPTION The headlight ECU sub-assembly LH receives steering angle signals from the steering sensor. The headlight ECU sub-assembly LH outputs DTC B2414. DTC No. Detection Item DTC Detection
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DESCRIPTION These DTCs are output when an internal malfunction in the headlight ECU sub-assembly occurs. The headlight ECU sub-assembly LH outputs DTC B242C and B242D. DTC No. Detection Item DT
Open in IG Circuit (B242E)
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SEE MORE:
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE HINT:
Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspect
Disassembly
DISASSEMBLY CAUTION / NOTICE / HINT NOTICE:
When using a vise, place aluminum plates between the part and vise.
When using a vise, do not overtighten it.
PROCEDURE 1. REMOVE STEERING LOCK ACTUATOR ASSEMBLY (a) Secure the electric power steering column sub-assembly in a vise. (b) Using a cent
