Help! Strange noise "Jill" with intermittent motor/fan turning on

Hi all, here are my thoughts on the latest posts...

I haven't noticed a pattern yet on the compressors we have replaced. The ones that come to mind are due to no compression (pressures equal high and low sides) and .... Noisy.

The fact that the noise in 2009Prius' car was NOT there until recently, indicates a changing condition even though some noise on startup of the compressor is normal. I would recommend replacement, provided the car is still under warranty. If the dealer is hesitant due to the very brief nature of the noise, remain politely persistant.

Be polite, but do not take no for an answer. Ask to speak to the factory rep if needed. In most cases, unless the situation is something that is simply a charectoristic of the vehicle and cannot be changed, the dealer will replace the part(s) in order to keep the customer happy.

Also ask them to check the A/C controls. Replacing the compressor will not solve the problem if the controls are keeping it running when it shouldn't be.

 

How does it work?? Here comes the information overload.... This is right out of the Toyota new car features guide for the 2004 Prius and the basic operation is still the same for the 2009. Unfortunately, the pictures did not copy and paste very well. Send me an email at [email protected] and I will reply with a PDF file atached with this info in a more readable condition....

BE-96 BODY ELECTRICAL ​

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— AIR CONDITIONING​

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CONSTRUCTION AND OPERATION
1. Air Conditioning Operation​

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On the ’03 Prius, the air conditioning was controlled at the air conditioning control panel. On the ’04 Prius,
this control operation has been changed to the switches that appear on the air conditioning screen display
of the multi display and the switches provided on the steering pad.​

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In addition to the air conditioning screen display, the operating conditions of the AUTO,
RECIRCULATION, front DEF, and rear DEF switches are indicated by the indicator lights in the
combination meter.​

255BE93 ​

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Steering Pad Switch
Multi Display​

AVC-LAN
Combination Meter
Gateway ECU
Meter ECU
BEAN
A/C ECU​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-97​

2. Air Conditioning Unit​

General​

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A semi-center location air conditioning unit, in which the evaporator and heater core are placed in the
vehicle’s longitudinal direction, has been adopted.​

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A 2-way flow type air conditioning unit that changes the 2-way flow operation if specified conditions
are met, is adopted. Under 2-way flow operation, the system introduces external air and internal air
simultaneously, discharges warm internal air to the foot area, and the fresh, dry external air to the upper
area. Thus, it realizes both excellent heating performance and demisting performance. For details, 2-way
flow control on see page BE-107.​

255BE94 ​

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Warm internal air to the footwell area
External Air
Fresh, dry external air to the upper area​

Construction​

A partition plate divides the inside of the air conditioning unit into two (External and internal air passages)
parts. Thus, by controlling the external air door and the internal air door separately, the external and internal
airs are introduced into the cabin in the following three modes.​

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FRESH AIR​

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RECIRC AIR​

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BI-LEVEL, FRESH AIR/ RECIRC AIR (2-way flow)​

181BE38​

Internal
Air
External
Air
DEF FACE
Internal Air
Partition
Plate
Heater Core FOOT
Internal Air Door Evaporator
Internal
Air
Internal External
Air Door
External Air​

BE-98 BODY ELECTRICAL ​

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— AIR CONDITIONING​

Evaporator​

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An RS (Revolutionary Slim) evaporator has been adopted.​

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By placing the tanks at the top and the bottom of the evaporator unit and adopting a micropore tube
construction, the following effects have been realized:
a) The heat exchanging efficiency has been improved.
b) The temperature distribution has been made more uniform.
c) The evaporator has been made thinner. 58 mm (2.3 in.) 38 mm (1.5 in.)​

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The evaporator body has been coated with a type of resin that contains an antibacterial agent in order
to minimize the source of foul odor and the propagation of bacteria. The substrate below this coating
consists of a chromate-free layer to help protect the environment.​

232BE19​

Aluminum
Matrix
Chromate Free
Layer
Nylon Layer
Antibacterial Agent
Cooling Fin
Micropore Tube
Tank
Tank​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-99​

Heater Core and PTC Heater​

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A compact, lightweight, and highly efficient straight flow (full-path flow) aluminum heater core is used.
A PTC (Positive Temperature Coefficient) heater has been built into the heater core tube.​

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The PTC heater contains electrodes that are interposed with a PTC element, to which current is applied
in order to warm the air that passes through the fin. For details, PTC heater control on see page BE-108.​

255BE95​

Warm Air
Core Tube
Cool Air
Warm Water
PTC Element Insulation Film
Fin
Electrodes
PTC Heater
Warm Water​

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PTC heater has been provided in the air duct at the footwell outlet in front of the air conditioning unit.
This PTC heater, which is a honeycombshaped PTC thermistor, directly warms the air that flows in the
duct.​

255BE96​

PTC Heaters​

BE-100 BODY ELECTRICAL ​

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— AIR CONDITIONING​

3. Condenser​

General​

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The ’04 Prius retains the sub-cool condenser from the ’03 Prius. However, in the ’04 Prius the condenser
core has been made more minute and the refrigerant volume reduced.​

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This condenser has adopted a sub-cool cycle for its cooling cycle system to improve heat-exchanging
efficiency.​

255BE97​

’04​

Modulator​

’03
BODY ELECTRICAL ​

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— AIR CONDITIONING​

Service Tip​

Amount of Refrigerant
Point in which Bubbles Disappear
Properly Recharged Amount
High Pressure​

241BE169​

BE-101​

Sub-Cool Cycle​

The sub-cool cycle consists of the condensing portion and the super-cooling portion, and has the gas-liquid
separator (modulator) located between the two portions. A liquid refrigerant passed though the modulator
is cooled again in the super-cooling portion to increase energy of the refrigerant itself, thus high-efficiency
of the cooling performance is provided.​

255BE98​

Super-Cooling Portion
Liquid Refrigerant
Gaseous Refrigerant
Modulator
Multi-Flow Condenser Condensing Portion
The point at which the air bubbles disappear in the refrigerant of the sub-cool cycle is lower than the
proper amount of refrigerant with which the system must be filled. Therefore, if the system recharged
with refrigerant based on the point at which the air bubbles disappear, the amount of refrigerant would
be insufficient. As a result, the cooling performance of the system will be affected. If the system is
overcharged with refrigerant, this will also lead to a reduced performance.
For the proper method of verifying the amount of the refrigerant and to recharge the system with
refrigerant, see the 2004 Prius Repair Manual (Pub. No. RM1075U).​

BODY ELECTRICAL ​

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— AIR CONDITIONING​

Service Tip
BE-102​

4. Compressor​

General​

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Instead of the SCS06 scroll compressor that is actuated by the engine on the ’03 Prius, the ’04 Prius has
newly adopted an ES18 Electric Inverter Compressor that is actuated by a built-in electric motor. Except
for the portion that is actuated by the electric motor, the basic construction and operation of this
compressor are the same as in the scroll compressor used on the ’03 Prius.​

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The electric motor is actuated by the alternating current power (201.6 V) supplied by the A/C inverter,
which is integrated in the hybrid system inverter. As a result, the air conditioning control system on the
’04 Prius is actuated without depending on the operation of the engine, thus realizing a comfortable air
conditioning system and low fuel consumption.​

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Due to the adoption of an electric inverter compressor, the compressor speed can be controlled at the
required speed calculated by the A/C ECU. Thus, the cooling and dehumidification performance and
power consumption have been optimized.​

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Low-moisture permeation hoses have been adopted for the suction and discharge hoses at the compressor
in order to minimize the entry of moisture into the refrigeration cycle.​

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The compressor uses high-voltage alternating current. If a short or open circuit occurs in the compressor
wiring harness, the HV ECU will cut off the A/C inverter circuit in order to stop the power supply to
the compressor.​

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For details on the Electric Inverter Compressor control effected by the A/C ECU, see page BE-110.​

255BE99​

Discharge Hose
Suction Hose
In order ensure the proper insulation of the internal high-voltage portion of the compressor and the
compressor housing, the ’04 Prius has adopted a compressor oil (ND11) with a high level of insulation
performance. Therefore, never use a compressor oil other than the ND11 type compressor oil or its
equivalent.​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-103​

Construction​

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The Electric Inverter Compressor consists of a spirally wound fixed scroll and variable scroll that form
a pair, a brushless motor, an oil separator, and a motor shaft.​

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The fixed scroll is integrated with the housing. Because the rotation of the shaft causes the variable scroll
to revolve while maintaining the same posture, the volume of the space that is partitioned by both scrolls
varies to perform the suction, compression, and the discharge of the refrigerant gas.​

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Locating the suction port directly above the scrolls enables direct suction, thus realizing improved
suction efficiency.​

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Containing a built-in oil separator, this compressor is able to separate the compressor oil that is
intermixed with the refrigerant and circulates in the refrigeration cycle, thus realizing a reduction in the
oil circulation rate.​

255BE100​

Variable Scroll
Motor Shaft
Discharge Port Brushless Motor
Oil Separator
Fixed Scroll​

BE-104 BODY ELECTRICAL ​

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— AIR CONDITIONING​

Operation​

1) Suction​

As the capacity of the compression chamber, which is created between the variable scroll and the fixed
scroll, increases in accordance with the revolution of the variable scroll, refrigerant gas is drawn in from
the intake port.​

2) Compression​

From the state at which the suction process has been completed, as the revolution of the variable scroll
advances further, the capacity of the compression chamber decreases gradually. Consequently, the
refrigerant gas that has been drawn in becomes compressed gradually and is sent to the center of the fixed
scroll. The compression of the refrigerant gas is completed when the variable scroll completes
approximately 2 revolutions.​

3) Discharge​

When the compression of the refrigerant gas is completed and the refrigerant pressure becomes high, the
refrigerant gas discharges through the discharge port located in the center of the fixed scroll by pushing
the discharge valve.​

165BE23​

Compression
Discharge
Fixed Scroll
Intake Port
Variable
Scroll
Discharge
Port
Suction​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-105​

5. Water Pump​

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Same as the ’03 Prius, an electrical water pump has been adopted. This provides a stable heater
performance even if the engine is stopped because of a function of the THS-II.​

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The ’04 Prius has adopted a new type of electrical water pump in which the water flow resistance has been
reduced. As a result, the bypass valve that was used on the ’03 Prius has been discontinued.​

255BE101​

from Engine
to Heater​

6. Room Temp. and Humidity Sensor​

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A humidity sensor function has been added to the room temperature sensor. By enabling the detection of
humidity in the vehicle interior, this function optimizes the amount of dehumidification effort during the
operation of the air conditioning system. As a result, the power consumption of the compressor has been
reduced and a comfortable level of humidity has been realized in the vehicle interior.​

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The humidity-sensing resistance film that is built into the humidity sensor absorbs and releases the
humidity in the vehicle interior. During the absorption and releasing processes, the humidity-sensing
resistance film expands (during the absorption of humidity) and contracts (during drying). The clearance
between the carbon particles in the humidity-sensing resistance film expands and contracts during
absorption and drying, thus changing the resistance between the electrodes. The A/C ECU determines the
humidity in the vehicle interior through the changes in the output voltage of the humidity sensor that are
caused by the resistance between the electrodes.​

255BE103​

Humidity Sensor Room Temp. Sensor
A/C ECU
Electrodes
Humidity-sensing Resistance Film
Relative Humidity
Low High
Output
Voltage
Low
High​

255BE102​

BODY ELECTRICAL ​

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— AIR CONDITIONING​

Service Tip
BE-106​

7. Blower Pulse Controller​

The blower pulse controller controls the voltage that is output to the blower motor in accordance with the
duty cycle signals that are input by the A/C ECU. It is characterized by a smaller amount of heat generation
than the blower controller used on the previous model. As a result, the power loss associated with the heat
generation of the conventional blower linear controller has been reduced, thus realizing low fuel
consumption.​

255BE105​

Duty Ratio (%)
30
13
Output
Voltage
(V)
M+
Blower
Pulse
Controller
SI
Duty Signal
A/C ECU
M- 4
95​

255BE104​

8. Clean Air Filter​

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A clean air filter (Standard type Particle Filter) that excels in the removal of dust and pollen, located in
the blower unit is provided.​

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This filter, which cleans the air in the cabin, is made of polyester. Thus, it can be disposed of easily as a
combustible material, a feature that is friendly the environment.​

255BE106​

Clean Air Filter
(standard type particle filter)
The clean air filter (standard type particle filter) on U.S.A. model should be changed at 30,000 miles.
On Canada model, it should be changed at 16,000 km. However, it varies with the use conditions (or
environment).​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-107​

9. Air Conditioning ECU​

General​

The air conditioning ECU has following control.
Control Outline
Fuzzy Control
(see page BE-109)
The fuzzy control determines the conformity levels of the
temperature deviation, ambient temperature, and solar radiation by
defining their respective mathematical functions. In addition, a fuzzy
calculation method is used to calculate the required outlet air
temperature (TAO) and the blower volume. Based on these
calculations, the A/C ECU effects the respective controls for the
outlet air temperature, blower volume, compressor, and air outlet.
Outlet Air
Temp.
Control
Air Mix
Damper
Control
In response to the temperature control switch setting, the required
outlet air temperature, evaporator temperature sensor, and engine
coolant temperature sensor compensations are used by the air mix
control damper control to calculate a tentative damper opening angle,
through an arithmetic circuit in the air mix damper, to arrive at a target
damper opening angle.
Blower
Control
Blower Motor
Start Up
Control
When the blower motor is started up, the A/C ECU transmits a blower
motor actuation signal with a low duty cycle ratio to the blower pulse
controller, which applies a low voltage to the blower motor, in order
to operate the blower motor for 3 seconds at a low speed. This is
designed to protect the blower pulse controller from a sudden start-up
voltage surge.
Manual Control Sets the blower speed according to operation of the blower switch.
Automatic
Control​

Step Less Air Volume Control:​

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When the AUTO switch located on the steering pad switch is
pushed, or the air conditioning screen display of the multi display
is touched, the A/C ECU automatically regulates the duty ratio to
the blower pulse controller in accordance with a calculation result
by the fuzzy control in order to deliver step less air volume.​

Warm-up Control:​

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When the air outlet is in the FOOT, BI-LEVEL, or FOOT/DEF
mode, the blower will not operate until the engine coolant
temperature increases above a prescribed value. When the
temperature increases above a prescribed value, the blower motor
operates at the LO speed.​

Time-Lagged Air Flow Control:​

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2 types of time-lagged air flow control (in accordance with the
detected by the evaporator temperature sensor) help prevent hot air
from being emitted from FACE or BI-LEVEL vent.​

Sunlight Air Flow Control:​

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Controls the blower speed in accordance with the intensity of the
sunlight when the air outlet mode is at FACE or BI-LEVEL. The
blower speed can be adjusted in response to the signal received
from the solar sensor.
(Continued)​

BE-108 BODY ELECTRICAL ​

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— AIR CONDITIONING
Control Outline
Air Outlet
Control
Manual Control Changes the air outlet in accordance with the selected position of the
mode select switch.
Automatic
Control​

Mode Damper Switching Servomotor Control:​

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When the AUTO switch is pushed, automatic control causes the
mode servomotor to rotate to a desired position in accordance with
the target damper opening, which is based on the calculation of the
TAO.​

Low-Temperature FOOT/DEF Control:​

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In accordance with the engine coolant temperature, ambient
temperature, amount of sunlight, required outlet temperature
(TAO), and vehicle speed conditions, this control automatically
switches the blower outlet between the FOOT/ DEF modes to
prevent the window from becoming fogged when the outside air
temperature is low.
Air Inlet
Control
Manual Control
Drives the air inlet servomotor according to the operation of the air
inlet control switch and fixes the dampers in the FRESH or RECIRC
position.
Automatic
Control​

Automatic RECIRC/ FRESH Control:​

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When the AUTO switch is pressed, the system controls the servo
motor in order to achieve the air inlet that has been calculated in
accordance with the TAO.​

DEF Mode Control:​

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When switching the mode switching switch to DEF mode, A/C
ECU turns MAX mode ON forcibly and switches to FRESH mode.​

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When switching the mode switching switch to FOOT/DEF mode,
A/C ECU switches to FRESH mode.
2-Way Flow Mode Control
At the time of selecting FRESH mode, A/C ECU will judge it as
2-way flow mode when the blower outlet is selected to FOOT or
FOOT/DEF, the tentative air mix damper opening angle is above the
specified value (MAX HOT), and either the blower volume is more
than the specified volume or the vehicle speed is less than the
specified speed.
Half Inlet Air Mode Control
At the time of selecting FRESH mode, A/C ECU will judge it as half
inlet air mode when the blower outlet mode is selected to FACE or
BI-LEVEL and TAO is more than the specified temperature, and
operates both outlet air introduction and inlet air circulation at the
same time.
Electric
Inverter
Compressor
Control
(see page
BE-110)
Compressor
Speed Control​

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The A/C ECU calculates the target speed of the compressor based
on the target evaporator temperature (which is calculated by the
room temperature sensor, humidity sensor, ambient temperature
sensor, and the solar sensor) and the actual evaporator temperature
that is detected by the evaporator temperature sensor in order to
control the compressor speed.​

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The A/C ECU calculates the target evaporator temperature, which
includes corrections based on the vehicle interior humidity (which
is obtained from the humidity sensor) and the windshield glass
inner surface humidity (which is calculated from the humidity
sensor, solar sensor, room temperature sensor, mode damper
position, and wiper operation condition). Accordingly, the A/C
ECU controls the compressor speed to an extent that would not
inhibit the proper cooling performance or defogging performance.
Electric Water Pump Control
When the blower motor is ON and the engine has been stopped by the
hybrid control, the A/C ECU turns ON the electric water pump in
accordance with the judgment of the air mix damper opening.
(Continued)​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-109​

Control Outline
Engine Start Request Control
To ensure the proper heater performance when the hybrid system is
started at low temperatures, the A/C ECU transmits an engine start
request to the HV ECU in accordance with the TAO, engine coolant
temperature sensor signal, and ambient temperature sensor signal.
PTC Heater Control
When the hybrid system is operating (READY), and the blower
motor is turned ON, the A/C ECU turns ON the PTC heater if the
conditions listed below are met.​

Heater core integrated PTC Heater​

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Air outlet is in the FOOT, FOOT/DEF or DEF mode.​

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Engine coolant temperature is below specified temperature.​

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Ambient temperature is below specified temperature (DEF mode).​

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Tentative air mix damper opening angle is above the specified
value. (MAX HOT)​

Footwell air duct integrated PTC heater​

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Air outlet is in the FOOT or FOOT/DEF mode.​

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Engine coolant temperature is below specified temperature.​

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Tentative air mix damper opening angle is above the specified
value. (MAX HOT)
Electric Cooling Fan Control The A/C ECU control the cooling fan in accordance with the vehicle
speed signal and compressor speed signal.
Rear Window
Defogger Control
Switches the rear defogger and outside rear view mirror heaters, on
for 15 minutes when the rear defogger switch is switched on.
Switches them off if the switch is pressed while they are operating.
Outer Temperature
Indication Control
Based on the signals from the ambient temperature sensor, this
control calculates the outside temperature, which is then corrected in
the air conditioning ECU, and shown in the multi display.
Self-
Diagnosis
Checks the sensor and A/C inverter in accordance with operation of
the air conditioning switches, then heater control panel display
portion a DTC (Diagnosis Trouble Code) to indicate if there is a
malfunction or not (sensor check function).
Drives the actuators through a predetermined sequence in accordance
with the operation of the air conditioning switches (actuator check
function).​

BE-110 BODY ELECTRICAL ​

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— AIR CONDITIONING​

Fuzzy Control​

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In the conventional automatic air conditioning control system, the A/C ECU calculates the required
outlet air temperature (TAO: Temperature Air Outlet) for the set temperature in accordance with a
prescribed calculation formula based on the temperature information obtained from the sensors. By
automatically controlling the servo motors and the blower motors in order to achieve the TAO that has
thus been calculated, this system maintains a stable temperature in the vehicle interior and ensures the
comfort of the occupants. However, the conventional automatic air conditioning control system that
univocally determines all controls based on the TAO offers a low level of freedom of control (as it was
an aggregation of linear systems). Therefore, the ’04 Prius has adopted fuzzy control (for non linear
control) in order to achieve fine-tuned control. The fuzzy control determines the conformity levels of
the temperature deviation, ambient temperature, and solar radiation by defining their respective
mathematical functions. In addition, it uses a fuzzy calculation method (algebraic product addition center
of gravity method) to calculate the required outlet air temperature (TAO) and the blower volume. Based
on these calculations, the A/C ECU effects the respective controls for the outlet air temperature, blower
volume, compressor, and air outlet.​

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The conformity levels for the temperature deviations are defined in 9 levels in accordance with the actual
room temperature and the set temperature, for the solar radiation in 4 levels (low, medium low, medium,
and high) in accordance with the solar sensor, and for the ambient temperatures in 6 levels (midwinter,
winter, spring-autumn, spring-summer, and midsummer) in accordance with the ambient temperature
sensor.​

255BE107​

Non-Linear Control (Fuzzy Control)​

Ambient
Temperature
Temperature
Deviation
Blower
Volume​

255BE108​

Conventional​

Ambient
Temperature
Temperature
Deviation
Blower
Volume​

BODY ELECTRICAL ​

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— AIR CONDITIONING BE-111​

Electric Inverter Compressor Control​

1) Compressor Speed Control​

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The A/C ECU calculates the target compressor speed based on the target evaporator temperature
(calculated from the room temperature sensor, humidity sensor, ambient temperature sensor, and solar
sensor) and the actual evaporator temperature detected by the evaporator temperature sensor. Then, the
A/C ECU transmits the target speed to the HV ECU. The HV ECU controls the A/C inverter based on
the target speed data in order to control the compressor to a speed that suits the operating condition of
the air conditioning system.​

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The A/C ECU calculates the target evaporator temperature, which includes corrections based on the
vehicle interior humidity (which is obtained from the humidity sensor) and the windshield glass inner
surface humidity (which is calculated from the humidity sensor, solar sensor, room temperature sensor,
mode damper position, and wiper operation condition). Accordingly, the A/C ECU controls the
compressor speed to an extent that does not inhibit the proper cooling performance or defogging
performance. As a result, comfort and low fuel consumption can be realized.​

255BE109​

Wiper Switch Wiper Motor Ambient Temp.
Sensor
Ambient Temp.
ECM
HV ECU
Inverter
Control
A/C Inverter
Target
A/C ECU Compressor Speed​

Calculates the
target compressor
speed in
accordance with
various input
conditions.​

Air Outlet
Damper
Position Sensor
Evaporator
Temp. Sensor
Solar Sensor
Humidity
Sensor
Room Temp.
Sensor
Electric Inverter
Compressor​

BE-112 BODY ELECTRICAL ​

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— AIR CONDITIONING​

Self-Diagnosis​

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The air conditioning ECU has a self-diagnosis function. It stores any operation failures in the air
conditioning system memory in the form of a malfunction code. By operating the air conditioning
control switches, the stored malfunction codes are displayed on the multi display. Since diagnostic
results are stored directly by electric power from the battery, they are not cleared even when the ignition
switch is turned off.​

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Functions ​

Function Outline
Indicator Check Checks mode and temperature setting display.
Sensor Check Checks the past and present malfunctions of the sensors and A/C inverter,
and clearing the past malfunction data.
Actuator Check Checks against actuator check pattern if blower motor, servomotors and
magnetic clutch are operating correctly according to signals from ECU.​

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The check function can be started by the following procedure shown below.​

241BE167​

*: Use the switches that are provided on the steering pad switch.​

Fr DEF*​

TEMP-*​

: Indicates a switch operation
Actuator Check
(Stepped Operation)
Actuator Check​

(Continuous Operation)​

If both AUTO* and R/F* switches
are not pressed at the same time.​

Cancel check Mode​

(Normal operation now possible)​

Sensor Check
(Stepped Operation)
Sensor Check​

(Continuous Operation)​

Indicator Check
(Continuous Operation)​

Power switch ON with AUTO*
and R/F* switches held down.​

TEMP-*​

AUTO*
R/F*
Fr DEF*
R/F*
AUTO*
R/F*​

AUTO*​

Fr DEF*
Fr DEF*​

TEMP-*
TEMP-*​

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For details on the indicator check, sensor check, actuator check function, and clearing DTC of this​

system, refer to the 2004 Prius Repair Manual (Pub. No. RM1075U).

 

Compressor replacement on a Prius is not difficult at all. It's actually a little easier thana normal car since there is no drive belt. Even though the compressor is powered by high voltage, once the car is turned off and allowed to sit for 10-15 minutes, there is no voltage left in the compressor and it can be safely replaced by aby qualified technician.

Any and all dealerships will be equipped to replace a compressor on a Prius whether under warranty or not.

The factory representative is pretty much what the title implies. He/she travels from dealer to dealer handling issues which are unable to be resolved by the dealership itself. Factory reps generally are only called in for situations in which a decision is required that the dealership's management is not authorized to make.
Example #1: A customer's car is 2000 miles past it's factory warranty period, but still within the time period for the warranty. There is an issue with the radio not working properly. The dealership is not authorized to replace the radio under warranty since the mileage has expired. The factory rep can make the decision to replace the radio at no charge to the customer, covering the repair under what is known as a Goodwill Policy.
Example #2: A customer hears a noise which the dealership's technicians determine to be a normal charectoristic of the vehicle, although it seems to be louder than most other vehicles of the same type. The dealership cannot replace the component since, technically, there is nothing wrong with it. The factory rep has the authority to offer a one time replacement to attempt to reduce the noise in an effort to improve customer satisfaction.

Basically the rep has the authority of Toyota behind him and works directly for Toyota, while the dealership management works for whomever owns the dealership.

If your car is still under the 3yr/36k warranty, visit your nearest dealer and ask them to compare your car to other similar Prius. Basically, any 2nd Gen Prius. If the other cars do not have the same sound, they should be more than happy to replace the compressor. Especially since that is how they make their money. As a tech, I may not get paid as much to replace a part under warranty as I do when the job is customer pay, but I still make a good living fixing cars. If I don't fix the car, I don't get paid.

 

Please let us know how this plays out.... You definitely have me interested...

 

Well, you are definitely walking in fully armed and prepared! My best advice at this point is to call ahead for an appointment (if they do appointments, some don't) give them plenty of time and ask to speak directly to the tech if at all possible. Eliminating one person in the chain of information can help prevent misscommunication. If you have the ability to show them the video you posted earlier it will also help. Please remember, polite persistence. The techs and the dealership people are actually on your side. They only get paid if they can solve your issue and fix your car. It's in their best interest to make you hap as well since Customer Satisfaction is so very important to Toyota right now.

I would also try to make extra time for the 90L Special Service Campaign, which entails reshaping your accelerator pedal to avoid floor mat interference. My shop just received the templates today and we have already corrected quite a few Prius. Good luck and please keep us informed!!