Last Modified: 11-20-2023 6.11:8.1.0 Doc ID: RM100000001R3Z1
Model Year Start: 2021 Model: Camry Prod Date Range: [10/2020 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): TERMINALS OF ECU; 2021 - 2024 MY Camry [10/2020 -        ]

TERMINALS OF ECU

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

*A

w/o Seat Heater

*B

w/ Seat Heater

*C

for Dual Type

*D

for Single Type

HINT:

  • Check from the rear of the connector while it is connected to the air conditioning amplifier assembly.
  • Make sure to wait at least 2 minutes after turning the ignition switch off before performing an ECU terminal inspection.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

K55-1 (SG-1) - Body ground

LG - Body ground

Ground for cooler (room temp. sensor) thermistor

Always

Below 1 V

K55-2 (SG-2) - Body ground

W - Body ground

Ground for thermistor assembly

Always

Below 1 V

K55-3 (SG-4) - Body ground

L - Body ground

Ground for air conditioner pressure sensor

Always

Below 1 V

K55-6 (S5-3) - K55-3 (SG-4)

GR - L

Power supply for air conditioner pressure sensor

Ignition switch ON

4.75 to 5.25 V

Ignition switch off

Below 1 V

K55-9 (MGC) - K54-4 (GND)*3

G - W-B

Magnetic clutch operation signal
  • Engine running
  • Blower switch: LO
  • A/C switch: Off

11 to 14 V
  • Engine running
  • Blower switch: LO
  • A/C switch: On

Below 1 V

K55-13 (TAM) - K55-2 (SG-2)

R - W

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

K55-14 (TR) - K55-1 (SG-1)

GR - LG

Cooler (room temp. sensor) 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

K55-20 (ECOS) - K54-4 (GND)*4

W - W-B

ECO switch assembly (electric parking brake switch assembly) signal
  • Ignition switch ON
  • ECO switch assembly (electric parking brake switch assembly): off

11 to 14 V
  • Ignition switch ON
  • ECO switch assembly (electric parking brake switch assembly): On

Below 1 V

K55-21 (LOCK) - K55-2 (SG-2)*3

B - W

A/C lock sensor signal
  • Engine running
  • Blower switch: LO
  • A/C switch: On

Pulse generation

(See waveform 1)

K55-24 (PRE) - K55-3 (SG-4)

W - L

Air conditioner pressure sensor signal
  • Engine running
  • Air conditioning system operating
  • Refrigerant pressure: Abnormal pressure (more than 2812 kPaG (28.7 kgf/cm2, 408 psi))

4.61 V or higher
  • Engine running
  • Air conditioning system operating
  • Refrigerant pressure: Abnormal pressure (less than 196 kPaG (2.0 kgf/cm2, 28 psi))

Below 0.74 V
  • Engine running
  • Air conditioning system operating
  • Refrigerant pressure: Normal pressure (less than 2812 kPaG (28.7 kgf/cm2, 408 psi) and more than 196 kPaG (2.0 kgf/cm2, 28 psi))

0.74 to 4.61 V

K54-1 (B) - K54-4 (GND)

LA-B - W-B

Power source (Back-up)

Always

11 to 14 V

K54-2 (IG+) - K54-4 (GND)

LA-GR - W-B

Power source (IG)

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V

K54-3 (SOL+) - K54-4 (GND)

R - W-B

Compressor solenoid operation signal
  • Engine running
  • Blower switch: LO
  • A/C switch: On

Pulse generation

(See waveform 2)

K54-4 (GND) - Body ground

W-B - Body ground

Ground for main power supply

Always

Below 1 V

K54-6 (BLW) - K54-4 (GND)

LG - W-B

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

Pulse generation

(See waveform 3)

K54-11 (CANH) - K54-12 (CANL)

SB - W

CAN communication system

CAN communication is performed

Pulse generation

K54-14 (LIN1) - K54-4 (GND)

W - W-B

LIN communication signal

Ignition switch ON

Pulse generation

(See waveform 4)

z28-2 (BUS G) - Body ground*1

-

Ground for BUS IC

Always

Below 1 V

z28-3 (BUS) - z28-2 (BUS G)*1

-

BUS IC control signal

Ignition switch ON

Pulse generation

(See waveform 5)

z28-4 (B BUS) - z28-2 (BUS G)*1

-

Power supply for BUS IC

Ignition switch off

11 to 14 V

z28-5 (SG) - Body ground*1

GR - Body ground

Ground for No. 1 cooler thermistor

Always

Below 1 V

z28-6 (TE) - z28-5 (SG)*1

GR - GR

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

z29-2 (1A) - Body ground*2

-

Ground for BUS IC

Always

Below 1 V

z29-3 (2A) - z29-2 (1A)*2

-

BUS IC control signal

Ignition switch ON

Pulse generation

(See waveform 5)

z29-4 (3A) - z29-2 (1A)*2

-

Power supply for BUS IC

Ignition switch off

11 to 14 V

z29-5 (4A) - Body ground*2

GR - Body ground

Ground for No. 1 cooler thermistor

Always

Below 1 V

z29-6 (5A) - z29-5 (4A)*2

GR - GR

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
  • *1: for Dual Type
  • *2: for Single Type
  • *3: for 2GR-FKS
  • *4: w/ Electric Parking Brake System

(a) Waveform 1:

Item

Content

Terminal No.

K55-21 (LOCK) - K55-2 (SG-2)

Tool Setting

200 mV/DIV., 10 ms./DIV.

Condition
  • Engine running
  • Blower switch: LO
  • A/C switch: On

(b) Waveform 2:

Item

Content

Terminal No.

K54-3 (SOL+) - K54-4 (GND)

Tool Setting

5 V/DIV., 500 μs./DIV.

Condition
  • Engine running
  • Blower switch: LO
  • A/C switch: On

(c) Waveform 3:

Item

Content

Terminal No.

K54-6 (BLW) - K54-4 (GND)

Tool Setting

2 V/DIV., 1 ms./DIV.

Condition
  • Ignition switch ON
  • Blower switch: LO

(d) Waveform 4:

Item

Content

Terminal No.

K54-14 (LIN1) - K54-4 (GND)

Tool Setting

2 V/DIV., 20 ms./DIV.

Condition

Ignition switch ON

(e) Waveform 5:

Item

Content

Terminal No.

z28-3 (BUS) - z28-2 (BUS G)*1

z29-3 (2A) - z29-2 (1A)*2

Tool Setting

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

Condition

Ignition switch ON
  • *1: for Dual Type
  • *2: for Single Type

CHECK AIR CONDITIONING CONTROL ASSEMBLY

HINT:

Check from the rear of the connector while it is connected to the air conditioning control assembly.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

K26-2 (IG+) - K26-6 (GND)

GR - W-B

Power source (IG)

Ignition switch off

Below 1 V

Ignition switch ON

11 to 14 V

K26-6 (GND) - Body ground

W-B - Body ground

Ground for air conditioning control assembly

Always

Below 1 V

K26-9 (LIN1) - Body ground

LG - Body ground

LIN communication signal

Ignition switch ON

Pulse generation

(See waveform)

K26-11 (ILL+) - Body ground

W - Body ground

Illumination signal

Light control switch in off position

Below 1 V

Light control switch in tail or head position

11 to 14 V

K26-15 (ILL-) - Body ground

B - Body ground

Illumination signal

Always

Below 1 V

(a) Waveform:

Item

Content

Terminal No.

K26-9 (LIN1) - Body ground

Tool Setting

2 V/DIV., 20 ms./DIV.

Condition

Ignition switch ON