ECO TOYOTA SUPRA 1995 Service Repair Manual

CAUTION:
wBe sure to connect both the high and low pressure
quick±connectors onto the A/C system when evacuating.
If only one side is connected, the system would be open
to atmosphere through the other connector, making it
impossible to maintain vacuum.
wBe sure to turn off the manifold gauge valve immediately
after evacuating the system. Then you may switch off the
vacuum pump.
PRECAUTIONS WHEN CHARGING
REFRIGERANT
1. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH
REFRIGERANT IN REFRIGERANT SYSTEM
If there is not enough refrigerant in the refrigerant system, oil
lubrication will be insufficient and compressor burnout may
occur, so take care to avoid this.
2. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE
WHILST COMPRESSOR IS OPERATING
If the high pressure valve is opened, refrigerant flows in the
reverse direction and could cause the charging cylinder to
rupture, so open and close the low pressure valve only.
3. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH
REFRIGERANT
If refrigerant is overcharged, it causes problems such as in-
sufficient cooling, poor fuel economy, engine overheating
etc.
SUPPLEMENTAL RESTRAINT SYSTEM
(SRS)
Failure to carry out service operations in the correct se-
quence could cause the supplemental restraint system to
deploy, possibly leading to a serious accident.
During removal or installation of the parts and the yellow wire
harness and connector for the airbag is necessary, refer to
the precautionary notices in the RS section before carrying
out operation. AC±6
± AIR CONDITIONING SYSTEMGENERAL DESCRIPTION

RECOMMENDED TOOLS
TOYOTA Electrical Tester Set
LUBRICANT 
 Item
 
 Capacity
 
 Classification
 Compressor oil ± ND±OIL 8 or equivalent
  When replacing receiver 10 cc (0.34 fl.oz.) 
  When replacing condenser 40 cc (1.4 fl.oz.) 
  When replacing evaporator 40 cc (1.4 fl.oz.) 
  When replacing compressor 140 cc (4.8 fl.oz.) 
AC±10± AIR CONDITIONING SYSTEMPREPARATION

PANEL DIAGNOSIS SYSTEM
If a trouble occurs in A/C system, the specified lamp on the control panel starts blinking during the diagnos-
tic sensor check.
During system diagnosis, a trouble is indicated on the panel by the blinking of a specified light instead of
a code display. (See TROUBLE CODE CHART)
For example, when a trouble occurs in solar sensor circuit, the LED for DEF mode switch will be blinking
during the diagnostic sensor check.
SWITCH
SWITCH NAMECODECODESWITCH NAMECODESWITCH NAME
LED
INDICATOR NAMECODEINDICATOR NAMECODEINDICATOR NAMECODE
AC±16± AIR CONDITIONING SYSTEMTROUBLESHOOTING

INDICATOR CHECK
1. Turn the ignition switch on while pressing the air conditioning
control AUTO switch and R/F SW simultaneously.
2. Check that all the indicators light up and go off at 1
second intervals 4 times in succession.
HINT:
wAfter the indicator check is ended, the diagnostic sensor
check begins automatically.
wPress the OFF switch when cancelling the check mode.
DIAGNOSTIC SENSOR CHECK
1. Perform an indicator check. After the indicator check is
completed, the system enters the diagnostic sensor check
mode automatically.
2. Check the LED blinking on the panel. Refer to the list of codes
on page AC±20 when translating the trouble code from the
LED blinking.
If the slower display is desired, press the RDEF switch and
change it to step operation. Each time the RDEF switch is
pressed, the blinking LED changes by 1 step.
CLEARING TROUBLE CODES' MEMORY
Method 1:
1. Pull out the ECU±B fuse in Junction Block No. 1 for 10 sec.
or longer to clear the trouble codes' memory.
2. After reinserting the fuse, check that the normal code is
output.
Method 2:
Press the RDEF switch while pushing the A/C switch during
the sensor check mode. AC±18
± AIR CONDITIONING SYSTEMTROUBLESHOOTING

MATRIX CHART OF PROBLEM SYMPTOMS
If a normal code is displayed during the diagnostic sensor check but the trouble still occurs, perform trouble-
shooting for each problem symptom, checking the circuits for each symptom in the order given in the table
below (Proceed to the page given for each circuit).
AC±28
AC±30
AC±32
AC±34
AC±36
AC±38
AC±40
AC±42
AC±44
AC±46
AC±48
AC±50See page
Suspect Area
Symptom
Whole functions of the A/C system does not operate.
No blower operation
No blower control
Insufficient air flow
No cool air comes out
No warm air comes out
Output air is warmer or colder than the set
temperature or response is slow
No temperature control
(only Max. cool or Max. warm)
No air inlet control
No air outlet control
Engine idle up does not occur, or is continuous
Blinking of A/C indicator
Trouble code not recorded.
Set mode is cleared when IG switch is turned off.
Temperature Control
Air Flow Control
Room temp. sensor circuitAmbient temp. sensor
circuitEvaporator temp. sensorcircuitSolar sensor circuitEngine coolant temp. sensor
circuitPressure switch circuitAir mix damper positionsensor circuitAir mix damper controlservo motor circuitAir inlet damper controlservo motor circuitAir outlet damper controlservo motor circuitCompressor lock sensorcircuitAir outlet damper positionsensor circuit
AC±26± AIR CONDITIONING SYSTEMTROUBLESHOOTING

HINT:
wIf the instruction ºProceed to next circuit inspection shown on matrix chart is given in the flow chart
for each circuit, proceed to the circuit with the next highest number in the table to continue the check.
wIf the trouble still reappears even though there are no abnormalities in any of the other circuits, then
check or replace the A/C amplifier.
AC±52
AC±54
AC±56
AC±58
AC±60
AC±62
AC±66
AC±69
IN±35
AC±71
AC±76
AC±77
AC±107
AC±92
AC±91
AC±95
AC±96
AC±98
AC±97
IG power source circuitBackup power source
circuitACC power source circuitHeater relay circuitCompressor circuitBlower motor circuitA/C amplifierTemperature set dial circuitA/C control assembly circuitRefrigeration system inspection
with manifold gauge setElectric cooling fanWater valveDrive belt tensionRefrigerant volumeCondenserExpansion valveEvaporatorHeater radiatorReceiver
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±27

Blinking Light A C Compressor Lock Sensor Circuit
CIRCUIT DESCRIPTION
This sensor sends 1 pulse per engine revolution to the A/C amplifier. If the number ratio of the compres-
sor speed divided by the engine speed is smaller than a predetermined value, the A/C amplifier turns
the compressor off. And, the indicator flashes at about 1 second intervals.
Diagnostic Sensor Check Detecting ConditionTrouble Area

Compressor
Compressor drive belt

Compressor lock sensor

Harness and connector between compressor and
A/C amplifier

A/C amplifierAll conditions below are detected for 3 secs. or more
(a) Engine speed: 450 rpm or more
(b) Ratio between engine and compressor speed
deviates 20% or more in comparison to normal
operation.
AC±38± AIR CONDITIONING SYSTEMTROUBLESHOOTING

2. MOISTURE PRESENT IN REFRIGERATION SYSTEM
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy

During operation, pres±
sure on low pressure
side sometimes
becomes a vacuum and
sometimes normal
Moisture entered in re±
frigeration system
freezes at expansion
valve orifice and tem±
porarily stops cycle, but
normal state is restored
after a time when the ice
melts(1) Replace receiver/drier
(2) Remove moisture in
cycle through repeat±
edly evacuating air
(3) Charge new refriger±
ant to proper amount
Drier in oversaturated
state

Moisture in refrigeration
system freezes at ex±
pansion valve orifice
and blocks circulation of
refrigerant
Condition: Periodically cools and then fails to cool
3. INSUFFICIENT REFRIGERANT
Symptom seen in
refrigeration system
Condition: insufficient cooling
Probable causeDiagnosisRemedy

Pressure low on both
low and high pressure
sides

Bubbles seen in sight
glass continuously

insufficient cooling
performance
Gas leakage at some
place in refrigeration
system
Insufficient refrigerant
in system

Refrigerant leaking(1) Check for gas leak
age with leak detec±
tor and repair if nec±
essary
(2) Charge refrigerant to
proper amount
(3) If pressure indicated
value is near 0 when
connected to gauge,
create the vacuum
after inspecting and
repairing the location
of the leak
AC±72± AIR CONDITIONING SYSTEMTROUBLESHOOTING

ELECTRIC COOLING FAN
ON±VEHICLE INSPECTION
Condenser Fan:
1. INSPECT CONDENCER
(a) Disconnect the fan connector.
(b) Connect battery and ammeter to the cooling fan connector.
(c) Check that the condenser fan rotates smoothly, and check
the reading on the ammeter.
Standard amperage:
6.0±7.4 A
(d) Reconect the fan connector.
2. CONNECT NEGATIVE (±) TERMINAL CABLE TO
BATTERY
Radiator Fan:
(See page EG±353)
COOLING FAN RELAYS INSPECTION
(See page EG±356)
ECT SWITCH
(in ENGINE RADIATOR)
(See page EG±356)
± AIR CONDITIONING SYSTEMELECTRIC COOLING FANAC±107

INTRODUCTIONHOW TO USE THIS MANUAL -
IN-1
HOW TO USE THIS MANUAL
To assist you in finding your way through the manual, the Section Title and major heading are given
at the top of every page.
PREPARATION
Preparation lists the SST (Special Service Tools), recommended tools, equipment, lubricant and SSM
(Special Service Materials) which should be prepared before beginning the operation and explains the
purpose of each one.
REPAIR PROCEDURES
Most repair operations begin with an overview illustration. It identifies the components and shows how
the parts fit together.
Example:
IN002-0T