2001 TOYOTA PRIUS air conditioning

I18160
ON
(+) (±)CF
RF
Terminal Condition Voltage
10 ± 14 V
Below 1.0 V
Below 1.0 V
10 ± 14 V Water temp.: Below 90°C (194 °F)
Refrigerant pressure:
Below 1,520 kPa (15.5 kgf/cm
2, 220 psi) RF e Body
ground
CF e Body
ground
Water temp.: Above 90°C (194 °F)
Refrigerant pressure:
Above 1,520 kPa (15.5 kgf/cm
2, 220 psi)
A/C switch: ON
A/C switch: OFF
DI±954
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals RF, CF of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Start engine.
(b) Turn A/C switch ON.
(c) Measure voltage between terminal RF, CF of A/C amplifi-
er and body ground at each conditions as shown in the
chart.
OK:
OK Go to step 4.
NG
2 Check Fan No. 1, No. 2 and No. 3 relays (See page AC±65).
NG Replace faulty relay
OK

I18394
Engine Room J/B
CDS Fuse
RDI Fuse
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±955
2001 PRIUS (RM778U)
3 Check RDI fuse and CDS fuse.
PREPARATION:
Remove RDI fuse and CDS fuse from engine room J/B.
CHECK:
Check continuity of RDI fuse and CDS fuse.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the RDI fuse (See attached
wiring diagram).
OK
Check harness and connector between A/C control amplifier and battery (See page IN±41).
4 Check fan motor operation (See page AC±67).
NG Replace fan motor.
OK
5 Check pressure switch (See page AC±62).
NG Replace pressure switch.
OK

DI±956
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
6 Check engine coolant temp. switch (See page AC±84).
NG Replace water temp. switch.
OK
7 Check harness and connector between A/C amplifier and pressure switch, pres-
sure switch and body ground (See page IN±41).
NG Repair and replace harness and connector.
OK
8 Check harness and connector between A/C amplifier and water temp. switch, wa-
ter temp. switch and body ground (See page IN±41).
NG Repair and replace harness and connector.
OK
Check and replace A/C amplifier.

AC2810
AC0Y9±05
AC2811
N11084
Wrong Okay
HI LO HILO
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±1
1889 Author: Date:
2001 PRIUS (RM778U)
AIR CONDITIONING SYSTEM
PRECAUTION
1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED
AREA OR WEAR A NAKED FLAME
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN
YOUR EYES OR ON YOUR SKIN
If liquid refrigerant gets in your eyes or on your skin.
(a) Wash the area with lots of cool water.
CAUTION:
Do not rub your eyes or skin.
(b) Apply clean petroleum jelly to the skin.
(c) Go immediately to a physician or hospital for professional
treatment.
4. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED
FLAME
5. BE CAREFUL NOT TO DROP CONTAINER AND NOT
TO APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT
ENOUGH REFRIGERANT IN REFRIGERATION SYS-
TEM
If there is not enough refrigerant in the refrigerant system oil lu-
brication will be insufficient and compressor burnout may occur,
so that care to avoid this, necessary care should be taken.
7. DO NOT OPEN PRESSURE MANIFOLD VALVE WHILE
COMPRESSOR IS OPERATE
If the high pressure valve is opened, refrigerant flows in the re-
verse direction and could cause the charging cylinder to rup-
ture, so open and close the only low pressure valve.
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH
REFRIGERANT
If refrigerant is overcharged, it causes problems such as insuffi-
cient cooling, poor fuel economy, engine overheating etc.

AC±2
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
1890 Author: Date:
2001 PRIUS (RM778U)
9. SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
The PRIUS is equipped with an SRS (Supplemental Restraint
System) such as the driver, front passenger and side airbag.
Failure to carry out service operation in the correct sequence
could cause the SRS to unexpectedly deploy during servicing,
possibly leading to a serious accident. Before servicing ( includ-
ing removal or installation of parts, inspection or replacement),
be sure to read the precautionary notices in the RS section.

AC0YB±04
I17971
ight Glass
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±3
2001 PRIUS (RM778U)
ON±VEHICLE INSPECTION
1. INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.
Test conditions:
MAX. switch ON
Blower speed control set at ºHIº
Temperature control set at ºMAX. COOLº
Running engine at 1,500 rpm
Fully open the doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer item 3 and 4
3No temperature difference between com-
pressor inlet and outletEmpty or nearly empty
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
4Temperature between compressor inlet and
outlet is noticeably differentCorrect or too muchRefer to items 5 and 6
5Immediately after air conditioning is turned
off, refrigerant in sight glass stays clearToo much
(1) Discharge refrigerant
(2) Evacuate air and charge proper amount
of purified refrigerant
6When air conditioning is turned off, refriger-
ant foams and then stays clearCorrect±
*: Bubbles in the sight glass with ambient temperatures higher than usual can be considered normal if cooling
is sufficient.

I01386
AC±4
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
2. INSPECT REFRIGERANT PRESSURE WITH MAN-
IFOLD GAUGE SET
This is a method in which the trouble is located by using a man-
ifold gauge set. Read the manifold gauge pressure when the
these conditions are established.
Test conditions:
Temperature at the air inlet with the switch set
at RECIRC is 30 ± 35 °C (86 ± 95 °F)
Engine running at 1500 rpm
Blower speed control switch at ºHIº position
Temperature control dial on ºCOOLº position
HINT:
It should be noted that the gauge indications may vary slightly
due to ambient temperature conditions.
(1) Normally functioning refrigeration system.
Gauge reading:
Low pressure side:
0.15 ± 0.25 MPa (1.5 ± 2.5 kgf/cm
2)
High pressure side:
1.37 ± 1.57 MPa (14 ± 16 kgf/cm
2)

I01387
Condition : Periodically cools and then fails to cool
I01388
Condition: Insufficient cooling
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±5
2001 PRIUS (RM778U)
(2) Moisture present in refrigeration system.
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
During operation, pressure on low
pressure side sometimes become
a vacuum and sometime normal
Moisture entered in refrigeration
system freezes at expansion valve
orifice and temporarily stops cycle,
by normal state is restored after a
time when the ice melts Drier oversaturated state
 Moisture in refrigeration system
freezes at expansion valve orifice
and blocks circulation of refriger-
ant(1) Replace condenser
(2) Remove moisture in cycle
through repeatedly evacuating air
(3) Charge proper amount of new
refrigerant
(3) Insufficient cooling
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low on both low and
high pressure sides
 Bubbles seen in sight glass con-
tinuously
 Insufficient cooling performance
Gas leakage at some place in re-
frigeration systemInsufficient refrigerant in sys-
tem
 Refrigerant leaking
(1) Check for gas leakage with gas
leak detector and repair if neces-
sary
(2) Charge proper amount of re-
frigerant
(3) If indicated pressure value is
near 0 when connected to gauge,
create the vacuum after inspecting
and repairing the location of the
leak