HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): TERMINALS OF ECU; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 - ]

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM1000000028C3D
Model Year Start: 2023	Model: GR Corolla	Prod Date Range: [11/2022 - ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): TERMINALS OF ECU; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 - ]

TERMINALS OF ECU

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

Channel 1 (m3)

Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
m3-2 (BUSG) - Body ground	Ground for BUS IC	Always	Below 1 Ω
m3-3 (BUS) - m3-2 (BUSG)	BUS IC control signal	Ignition switch ON	Pulse generation (See waveform "Servo LIN communication")
m3-4 (BUSB) - m3-2 (BUSG)	Power supply for BUS IC	Ignition switch off	11 to 14 V
m3-5 (SG-3) - Body ground	Ground for evaporator temp. sensor (No. 1 cooler thermistor)	Always	Below 1 Ω
m3-6 (TE) - m3-5 (SG-3)	Evaporator temp. sensor (No. 1 cooler thermistor) signal	Ignition switch ON Evaporator temperature: 0°C (32°F)	1.7 to 2.1 V
m3-6 (TE) - m3-5 (SG-3)	Evaporator temp. sensor (No. 1 cooler thermistor) signal	Ignition switch ON Evaporator temperature: 15°C (59°F)	0.9 to 1.3 V

Channel 2 (I49)

Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
I49-2 (CANH) - I49-1 (CANL)	CAN communication system	Ignition switch ON	Pulse generation
I49-5 (B) - I49-17 (GND)	Power source (Back-up)	Ignition switch off	11 to 14 V
I49-6 (IG+) - I49-17 (GND)	Power source (IG)	Ignition switch ON	11 to 14 V
I49-6 (IG+) - I49-17 (GND)	Power source (IG)	Ignition switch off	Below 1 V
I49-7 (LIN1) - I49-17 (GND)	LIN communication signal	Ignition switch ON	Pulse generation (See waveform "Control panel LIN communication")
I49-17 (GND) - Body ground	Ground for main power supply	Always	Below 1 Ω
I49-18 (SOL+) - Body ground	Compressor solenoid operation signal	Engine running Blower switch: LO A/C switch: On	Pulse generation (See waveform "Compressor solenoid")
I49-21 (BLW) - I49-17 (GND)	Blower motor speed control signal	Ignition switch ON Blower switch: LO	Pulse generation (See waveform "Blower")

Channel 3 (I48)

Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
*: w/o Automatic Light Control
I48-1 (TAM) - I48-14 (SG-2)	Ambient temp. sensor (thermistor assembly) signal	Ignition switch ON Ambient temperature: 25°C (77°F)	1.05 to 1.45 V
I48-1 (TAM) - I48-14 (SG-2)	Ambient temp. sensor (thermistor assembly) signal	Ignition switch ON Ambient temperature: 40°C (104°F)	0.64 to 0.87 V
I48-2 (S5-1) - I49-17 (GND)*	Power supply for solar sensor (cooler thermistor)	Ignition switch ON	4.5 to 5.5 V
I48-2 (S5-1) - I49-17 (GND)*	Power supply for solar sensor (cooler thermistor)	Ignition switch off	Below 1 V
I48-3 (SG-1) - Body ground	Ground for room temp. sensor (cooler thermistor)	Always	Below 1 Ω
I48-5 (TR) - I48-3 (SG-1)	Room temp. sensor (cooler thermistor) signal	Ignition switch ON Cabin temperature: 25°C (77°F)	1.05 to 1.45 V
I48-5 (TR) - I48-3 (SG-1)	Room temp. sensor (cooler thermistor) signal	Ignition switch ON Cabin temperature: 40°C (104°F)	0.64 to 0.87 V
I48-6 (PRE) - I48-15 (SG-4)	Air conditioning pressure sensor signal	Engine running Air conditioning system operating Refrigerant pressure: Normal pressure	0.74 to 4.61 V
I48-9 (TS) - I49-17 (GND)*	Solar sensor (cooler thermistor) signal	Ignition switch ON Solar sensor (cooler thermistor) subjected to electric light	0.8 to 4.3 V
I48-9 (TS) - I49-17 (GND)*	Solar sensor (cooler thermistor) signal	Ignition switch ON Solar sensor (cooler thermistor) covered with cloth	Below 0.8 V
I48-11 (S5-3) - I48-15 (SG-4)	Power supply for air conditioning pressure sensor	Ignition switch ON	4.75 to 5.25 V
I48-11 (S5-3) - I48-15 (SG-4)	Power supply for air conditioning pressure sensor	Ignition switch off	Below 1 V
I48-14 (SG-2) - Body ground	Ground for ambient temp. sensor (thermistor assembly)	Always	Below 1 Ω
I48-15 (SG-4) - Body ground	Ground for air conditioning pressure sensor	Always	Below 1 Ω

(a) Waveform "Servo LIN communication":

Item	Content
Terminal No.	m3-3 (BUS) - m3-2 (BUS G)
Tool Setting	2 V/DIV., 2 ms./DIV.
Condition	Ignition switch ON

(b) Waveform "Compressor solenoid":

Item	Content
Terminal No.	I49-18 (SOL+) - Body ground
Tool Setting	5 V/DIV., 500 ms./DIV.
Condition	Engine running Blower switch: LO A/C switch: On

(c) Waveform "Control panel LIN communication":

Item	Content
Terminal No.	I49-7 (LIN1) - I49-17 (GND)
Tool Setting	2 V/DIV., 20 ms./DIV.
Condition	Ignition switch ON

(d) Waveform "Blower":

Item	Content
Terminal No.	I49-21 (BLW) - I49-17 (GND)
Tool Setting	2 V/DIV., 1 ms./DIV.
Condition	Ignition switch ON Blower switch: LO

HINT:

The waveform varies with the blower speed.

CHECK AIR CONDITIONING CONTROL ASSEMBLY

Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
I37-7 (LIN1) - Body ground	LIN communication signal	Ignition switch ON	Pulse generation (See waveform)
I37-9 (IG+) - I37-13 (GND)	Power source (IG)	Ignition switch off	Below 1 V
I37-9 (IG+) - I37-13 (GND)	Power source (IG)	Ignition switch ON	11 to 14 V
I37-13 (GND) - Body ground	Ground for air conditioning control assembly	Always	Below 1 V

(a) Waveform:

Item	Content
Terminal No.	I37-7 (LIN1) - Body ground
Tool Setting	2 V/DIV., 20 ms./DIV.
Condition	Ignition switch ON