Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM100000001GW8O
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 -           ]
Title: HEATING / AIR CONDITIONING: SOLAR SENSOR: ON-VEHICLE INSPECTION; 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT AUTOMATIC LIGHT CONTROL SENSOR (w/ Automatic Light Control)

(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.

2. INSPECT COOLER (SOLAR SENSOR) THERMISTOR (w/o Automatic Light Control)

(a) Check the wire harness.

(1) Disconnect the m5 cooler (solar sensor) thermistor connector.

(2) Disconnect the I48 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

m5-1 - I48-2 (S5-1)

Always

Below 1 Ω

M5-2 - I48-9 (TS)

Always

Below 1 Ω

m5-1 - Body ground

Always

10 kΩ or higher

m5-2 - Body ground

Always

10 kΩ or higher
  • If the resistance is not as specified, repair the wire harness.

(4) Reconnect the I48 air conditioning amplifier assembly connector.

(5) Turn the power switch on (IG).

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

m5-1 - m5-2

Power switch off

Below 1 V

m5-1 - m5-2

Power switch on (IG)

4.5 to 5.5 V
  • If the voltage is not as specified, replace the air conditioning amplifier assembly.

(b) Check the cooler (solar sensor) thermistor.

(1) Reconnect the m5 cooler (solar sensor) thermistor connector.

(2) Turn the power switch on (IG).

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

1 - 2

Sensor subjected to electric light

0.8 to 4.3 V

1 - 2

Sensor covered with cloth

Below 0.8 V

NOTICE:

  • The connection procedure for using a digital tester such as a TOYOTA electrical tester is shown above. When using an analog tester, connect the negative (-) lead to terminal 1 and the positive (+) lead to terminal 2 of the cooler (solar sensor) thermistor.
  • Do not bring the positive and negative tester probes too close to each other as a short circuit may occur.

HINT:

  • Use an incandescent light for inspection. Bring it within about 30 cm (11.8 in.) of the cooler (solar sensor) thermistor.
  • As the inspection light is moved away from the sensor, the voltage decreases.
  • Check from the rear of the connector while it is connected to the cooler (solar sensor) thermistor.
  • If the voltage is not as specified, replace the cooler (solar sensor) thermistor.

*a

Component with harness connected

(Cooler (Solar Sensor) Thermistor)