Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000026Z3O
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): TERMINALS OF ECU; 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]

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
  • 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
*: w/ PTC heater (quick heater assembly)

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

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

I49-21 (BLW) - I49-17 (GND)

Blower motor speed control signal
  • Ignition switch ON
  • Blower switch: LO

Pulse generation

(See waveform "Blower")

I49-23 (PTC1) - Body ground*

Quick heater relay (PTC HTR No.1) operation signal
  • Ignition switch ON
  • PTC heater operating

Below 1 V

Channel 3 (I48)

Terminal No.

(Symbol)

Terminal Description

Condition

Specified Condition
*: w/ PTC heater (quick heater assembly)

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
  • Ignition switch ON
  • Ambient temperature: 40°C (104°F)

0.64 to 0.87 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
  • 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
  • Ignition switch ON (READY)
  • Air conditioning system operating
  • Refrigerant pressure: Normal pressure

0.74 to 4.61 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

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

I48-16 (PTC2) - Body ground*

Quick heater relay (PTC HTR No.2) operation signal
  • Ignition switch ON
  • PTC heater operating

Below 1 V

I48-17 (PTC3) - Body ground*

Quick heater relay (PTC HTR No.3) operation signal
  • Ignition switch ON
  • PTC heater operating

Below 1 V

(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 "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

(c) 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

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

HYBRID VEHICLE CONTROL ECU

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