Toyota Tundra. Manual — part 2387

Fig. 5: Air Conditioning System (Automatic) Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Communication table

COMMUNICATION CHART

Sender

Receiver

Signal

Line

Integration Control and Panel Air Conditioning Amplifier A/C control signal

LIN



Engine signal

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

SYSTEM DESCRIPTION

1. GENERAL

a. The air conditioning system has the following controls:

CONTROL AND OUTLINE CHART

ECM

Air Conditioning Amplifier



Engine speed coolant temperature CAN

Control

Outline

Outlet Air

Temperature

Control

Based on the temperature set by the temperature control switch, the neural
network control calculates the outlet air temperature based on the input signals
from various sensors.
The temperature setting for the driver and front passenger are controlled
independently in order to provide different vehicle interior temperatures for the
right and left side of the cabin. As a result, the air conditioning system
accommodates the occupants' preferences.

Blower Control

Controls the blower motor in accordance with the airflow volume that has been
calculated by the neural network control based on the input signals from various
sensors.

Air Outlet

Control

Automatically switches the air outlets in accordance with the outlet mode that has
been calculated by the neural network control based on the input signals from
various sensors.
In accordance with the engine coolant temperature, outside air temperature,
amount of sunlight, required blower, outlet temperature, and vehicle speed
conditions, this control automatically switches the blower outlet to the
FOOT/DEF mode to prevent the windows from becoming fogged when the
outside air temperature is low.

Air Inlet

Control

Automatically controls the air inlet control damper to achieve the calculated
required outlet air temperature. Drives the servo motor (for air inlet) according to
the operation of the air inlet control switch and moves the dampers to the FRESH
or RECIRC position.

Compressor

Control

Through the calculation of the target evaporator temperature based on various
sensor signals, the air conditioning amplifier optimally controls the discharge
capacity by regulating the opening extent of the air conditioning compressor
solenoid valve.
The air conditioning amplifier compares the pulley speed signals, which are
transmitted by the lock sensor located on the air conditioning compressor, with
the engine speed signals, which are transmitted by the ECM (crankshaft position
sensor). When the air conditioning amplifier determines that the pulley is locked,
it turns off the magnetic clutch.

Neural Network

Control

This control is capable of effecting complex control by artificially simulating the
information processing method of the nervous system of living organisms in
order to establish a complex input/output relationship that is similar to a human
brain.

Self-Diagnosis

A DTC (Diagnostic Trouble Code) is stored in the memory when the air
conditioning amplifier detects a problem with the air conditioning system.

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

2. MODE POSITION AND DAMPER OPERATION (for Double Cab)

a. Mode Position and Damper Operation

Fig. 6: Mode Position And Damper Operation Diagram (For Double Cab)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Functions of Main Dampers:

FUNCTIONS OF MAIN DAMPERS

Control

Damper

Operation Position

Damper

Position

Operation

Air Inlet

Control

Damper

FRESH

B

Brings in fresh air.

RECIRC

A

Recirculates internal air.

Air Mix

Control

MAX COLD to

MAX HOT

C - E
F - H

Varies the mixture ratio of fresh air and recirculated
air in order to regulate the temperature

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

3. MODE POSITION AND DAMPER OPERATION (for CrewMax)

a. Mode Position and Damper Operation

Damper

Temperature Setting

I - K

continuously from HOT to COLD.

Cool Air

Bypass

Damper

MAX COLD to

MAX HOT

Temperature Setting

U, V

Cool air blows out of the front center register and
side registers in order to adjust the temperature
around the head of the occupant during cooling or
warming.

Air Outlet

Control

Damper

FACE

O, P, T, W

Air blows out of the front center register, side
registers, and footwell ducts.*1

BI-LEVEL

M, P1, S,

W

Air mainly blows out of the front center register,
side register, and footwell ducts.

FOOT

M, Q, R',

X

Air mainly blows out of the front and rear footwell
ducts. In addition, air blows out slightly from the
front and side defrosters, front center register, and
side register.*2

FOOT/DEF

M, P', R',

Y'

Air mainly blows out of the front and side
defrosters to defrost the windshield; air also blows
out from the front and rear footwell ducts, front
center register, and side register.*2

DEF

O, P, R, Y

Air blows out of the front and side defrosters and
side registers to defrost the windshield.

HINT:
*1: In multi mode, air blows out of all the air outlets except the front and side defrosters.
*2: In multi mode, air blows out of all the air outlets.

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra