Last Modified: 06-05-2026 6.11:8.1.0 Doc ID: RM100000001GTRQ
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 -           ]
Title: LIGHTING (EXT): AUTOMATIC LIGHT CONTROL SENSOR: ON-VEHICLE INSPECTION; 2020 - 2026 MY GR Corolla Corolla Corolla Hatchback Corolla HV [01/2019 -        ]

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT AUTOMATIC LIGHT CONTROL SENSOR

(a) Disconnect the h1 automatic light control sensor connector.

*a

Front view of wire harness connector

(to Automatic Light Control Sensor)

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

Standard Voltage

Tester Connection

Condition

Specified Condition

*1: for HV Model

*2: for Gasoline Model

h1-1 (CLTB) - h1-2 (CLTE)

Power switch off*1

Below 1 V

Engine switch off*2

Power switch on (IG)*1

11 to 14 V

Engine switch on (IG)*2

Standard Resistance

Tester Connection

Condition

Specified Condition

h1-2 (CLTE) - Body ground

Always

Below 1 Ω

If the result is not as specified, there may be a malfunction on the wire harness side.

(c) Connect the h1 automatic light control sensor connector.

(d) Connect an oscilloscope to terminals h1-2 (CLTE) and h1-4 (CLTS) of the automatic light control sensor connector and check the waveform.

*a

Component with harness connected

(Automatic Light Control Sensor)

*b

Waveform

OK

Tester Connection

Condition

Tool Setting

Specified Condition

*1: for HV Model

*2: for Gasoline Model

h1-2 (CLTE) - h1-4 (CLTS)

Power switch on (IG)*1

2 V/DIV., 10 ms./DIV.

Pulse generation

(See waveform)

Engine switch on (IG)*2

HINT:

The communication waveform changes according to the surrounding brightness.

If the result is not as specified, the automatic light control sensor may be malfunctioning.