cooling TOYOTA PRIUS 2001 Service User Guide

THS (TOYOTA HYBRID SYSTEM)
182TH20
Cooling FanAir Intake
HV Battery Exhaust Duct No.2Exhaust Duct No.141
HV BATTERY COOLING SYSTEM
DESCRIPTION
When the temperature of the HV battery rises, the battery ECU executes a command to cause the cooling fan
to operate from OFF to LO, MID and HI speeds. However, if the air conditioning is being used at that time
to cool the vehicle's interior, and if there is still some margin left in the temperature of the HV battery, the
battery ECU keeps the fan OFF or running at LO speed, thus giving priority to the air conditioning.
The air intake for the cooling fan is located above the package tray trim. If an object (such as clothing) is
placed over this area, the HV battery might not be able to cool sufficiently, which could cause the output con-
trol warning light to illuminate.
CONSTRUCTION
This system feature a cooling fan which is driven by DC motor.

Specifications 
TypeSirocco Fan
Fan Size Dia x H mm (in.)100 x 40 (4.0 x 1.6)
Motor TypeDC Motor
Lo50
Air Flow Volume m3/hMid100
Hi150
Power Consumption W60
The operation of the cooling fans is controlled by the signals that are output by the battery ECU, which
monitors the temperature of the HV battery.

BODY ELECTRICAL ± AIR CONDITIONING
163BE17
Inner FinAntibacterial Agent
Nylon Layer
Chromate Layer
Aluminum
Matrix
182BE48
ModulatorMulti-Flow Condenser
Condensing Portion
Gaseous Refrigerant
Liquid Refrigerant
Super-Cooling Portion 158
Evaporator
By placing the tanks at the top and the bottom of the evaporator unit and by adopting an inner fin construc-
tion, the heat exchanging efficiency has been improved and the evaporator unit's temperature distribution
has been made more uniform. As a result, it has become possible to realize a thinner evaporator construction.
Furthermore, 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.
2. Condenser
The Prius has adopted sub-cool condenser in which a multi-flow condenser (consisting of two cooling por-
tions: a condensing portion and a super-cooling portion) and a gas-liquid separator (modulator) have been
integrated. This condenser has adopted the sub-cool cycle for its cooling cycle system to improve the heat
exchanging efficiency.
This condenser is integrated with the radiator to minimize the space they occupy in the engine compartment.
For details, see page 54 in the Engine Cooling System Section.
Sub-Cool Cycle
In the sub-cool cycle of the sub-cool condenser that has been adopted, after the refrigerant passes through
the condensing portion of the condenser, both the liquid refrigerant and the gaseous refrigerant that could
not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the evaporator
in an almost completely liquefied state.

BODY ELECTRICAL ± AIR CONDITIONING
152BE40
High Pressure
Properly Recharged Amount
Point in which Bubbles Disappear
Amount of Refrigerant159
NOTE: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 is 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.
For the proper method of verifying the amount of the refrigerant and to recharge the system with refrig-
erant, see the 2001 Prius Repair Manual (Pub. No.RM778U).

BODY ELECTRICAL ± AIR CONDITIONING 172
3) Refrigerant Pressure Malfunction Detection
By monitoring the pressure switch signal, this system can judge the refrigerant pressure to be abnormal,
and turns off the compressor magnetic clutch relay, if the pressure switch remains off.
4) MAX Switch ON Control
a. General
In case of usual air conditioning operation, the air conditioning system shows superior control on cool-
ing performance and fuel efficiency by combining the engine ON / OFF control by the hybrid control
and the air conditioning ON / OFF control.
In this MAX switch ON control, it controls by attaching greater importance to cooling performance of
the air conditioning.

DTC No.
Indicates the diagnostic trouble code.

Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs.

Detection Item
Indicates the system of the problem or
contents of the problem.
Trouble Area
Indicates the suspect area of the
problem.
Mass Air Flow Circuit MalfunctionDetection Item

Open or short in mass air flow meter circuit

Mass air flow meter

ECM DTC No.
(See page)Trouble AreaMIL* MemoryP0100
(DI±24)
P0101
(DI±28)
P0115
(DI±33)
Open or short in intake air temp. sensor
circuit

Intake air temp. sensor

ECM Intake Air Temp. Circuit
Malfunction P0110
(DI±29)

Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
Throttle/ Pedal Position Sensor/Switch
ºAº Circuit MalfunctionEngine Coolant Temp.
Circuit Malfunction

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
DTC CHART (SAE Controlled)
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument or other
factors.
If a malfunction code is displayed during the DTC check mode, check the circuit for that code listed in the table
below. For details of each code, turn to the page referred to under the ºSee pageº for the respective ºDTC No.º
in the DTC chart.
Mass Air Flow Circuit
Range/ Performance Problem
Mass air flow meter

Throttle position sensor Throttle/ Pedal Position Sensor/ Switch
ºAº Circuit Range / Performance Prob-
lem P0116
(DI±37)Engine Coolant Temp.
Circuit Range/ Performance Problem
Engine coolant temp. sensor

Cooling system
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±37
2001 PRIUS (RM778U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This table permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is shown below as an example.

PP3AY±01
± PREPARATIONCOOLING
PP±11
72 Author: Date:
2001 PRIUS (RM778U)
COOLING
SST (Special Service Tools)
09960±10010Variable Pin Wrench Set
(09962±01000)Variable Pin Wrench Arm Assy
(09963±00600)Pin 6

PP2FG±02
PP±12
± PREPARATIONCOOLING
2001 PRIUS (RM778U)
RECOMMENDED TOOLS
09082±00040TOYOTA Electrical Tester.

PP2FH±02
± PREPARATIONCOOLING
PP±13
2001 PRIUS (RM778U)
EQUIPMENT
Belt tension gauge
HeaterThermostat
Radiator cap tester
ThermometerThermostat
Torque wrench
Vernier calipers

PP2FI±03
PP±14
± PREPARATIONCOOLING
2001 PRIUS (RM778U)
COOLANT
ItemCapacityClassification
Engine coolant4.9 liters (5.2 US qts, 4.3 lmp. qts)Ethylene±glycol base

SS174±03
SS±6
± SERVICE SPECIFICATIONSENGINE MECHANICAL
128 Author: Date:
2001 PRIUS (RM778U)
ENGINE MECHANICAL
SERVICE DATA
Compression
pressureat 250 rpm STD
Minimum
Difference between each cylinder728 kPa (7.4 kgf/cm2, 106 psi)
534 kPa (5.4 kgf/cm2, 77 psi)
98 kPa (1.0 kgf/cm2, 14 psi)
Valve
clearance
at cold Intake
Exhaust
Valve lifter for repair part No. 06
No. 08
No. 10
No. 12
No. 14
No. 16
No. 18
No. 20
No. 22
No. 24
No. 26
No. 28
No. 30
No. 32
No. 34
No. 36
No. 38
No. 40
No. 42
No. 44
No. 46
No. 48
No. 50
No. 52
No. 54
No, 56
No. 58
No. 60
No. 62
No. 64
No. 66
No. 68
No. 70
No. 72
No. 740.17 ± 0.23 mm (0.007 ± 0.009 in.)
0.27 ± 0.33 mm (0.011 ± 0.013 in.)
5.060 mm (0.1992 in.)
5.080 mm (0.2000 in.)
5.100 mm (0.2008 in.)
5.120 mm (0.2016 in.)
5.140 mm (0.2024 in.)
5.160 mm (0.2031 in.)
5.180 mm (0.2039 in.)
5.200 mm (0.2047 in.)
5.220 mm (0.2055 in.)
5.240 mm (0.2063 in.)
5.260 mm (0.2071 in.)
5.280 mm (0.2079 in.)
5.300 mm (0.2087 in.)
5.320 mm (0.2094 in.)
5.340 mm (0.2102 in.)
5.360 mm (0.2110 in.)
5.380 mm (0.2118 in.)
5.400 mm (0.2126 in.)
5.420 mm (0.2134 in.)
5.440 mm (0.2142 in.)
5.460 mm (0.2150 in.)
5.480 mm (0.2157 in.)
5.500 mm (0.2165 in.)
5.520 mm (0.2173 in.)
5.540 mm (0.2181 in.)
5.560 mm (0.2189 in.)
5.580 mm (0.2197 in.)
5.600 mm (0.2205 in.)
5.620 mm (0.2213 in.)
5.640 mm (0.2220 in.)
5.660 mm (0.2228 in.)
5.680 mm (0.2236 in.)
5.700 mm (0.2244 in.)
5.720 mm (0.2252 in.)
5.740 mm (0.2260 in.)
Ignition timing7 ± 15° BTDC @ idle
Idle speedw/ Cooling fan off1,000 ± 50 rpm (A/C OFF)
1,200 ± 50 rpm (A/C ON)
Chain and
timing sprocketChain length at 16 linksMaximum
Camshaft timing sprocket wear (w/ chain) Minimum
Crankshaft timing sprocket wear (w/ chain) Minimum123.2 mm (4.850 in.)
96.2 mm (3.787 in.)
50.5 mm (1.988 in.)
Chain
tensioner
slipper and
vibration
damperWear Maximum1.0 mm (0.039 in.)