TOYOTA SUPRA 1995 Service Owner's Manual
Manufacturer: TOYOTA, Model Year: 1995, Model line: SUPRA, Model: TOYOTA SUPRA 1995Pages: 2543, PDF Size: 53.25 MB
Page 21 of 2543
AC±28
AC±30
AC±32
AC±34
AC±36
AC±38
AC±40
AC±42
AC±48
AC±42
AC±44
AC±48
AC±50
Trouble AreaMemory*5See page
(8.5 min. or more)
(8.5 min. or more)
(8.5 min. or more)
(8.5 min. or more)
(8.5 min. or more)
(1 min. or more)
(1 min. or more)
(15 secs. or more)
(15 secs. or more)
Room temp. sensorHarness or connector between room temp. sensor and A/C amplifier
A/C amplifier
Ambient temp. sensorHarness or connector between ambient temp. sensor and A/C amplifier
A/C amplifier
Evaporator temp. sensorHarness or connector between evaporator temp. sensor and A/C amplifier
A/C amplifier
Engine coolant temp. sensorHarness or connector between coolant temp. sensor and A/C amplifier
A/C amplifier
Solar sensorHarness or connector between sensor and A/C amplifier
A/C amplifier
Compressor drive beltCompressor lock sensorCompressorHarness and connector between A/C amplifier and compressor, compressor
lock sensor
A/C amplifier
Pressure switchHarness or connector between pressure switch and A/C amplifier
Refrigerant pipe lineA/C amplifier
Air mix damper position sensor A/C amplifierHarness or connector between air mix damper position sensor and A/C amplifier
Air outlet damper position sensor A/C amplifierHarness or connector between max cool damper position sensor and A/C amplifi-
er
Air mix damper control servo motorAir mix damper position sensorHarness and connector between A/C amplifier and air mix position sensor
Harness and connector between A/C amplifier and air mix damper controlservo motorA/C amplifier
Air outlet damper control servo motor Air outlet damper position sensorHarness and connector between A/C amplifier and air outlet position sensor
Harness and connector between A/C amplifier and air outlet damper motorA/C amplifier
HINT: *4Compressor lock (A/C light blink) is indicated only for a current malfunction. (See page AC±38)
To confirm the trouble indication, perform the following steps.
(1) With the engine ON, enter the trouble code check mode.
(2) Press the R/F switch to enter actuator check mode, and set the operation to Step No. 3.
(3) Press the AUTO switch to return to diagnostic sensor check mode.
(4) The A/C light starts to blink after approx. 3 secs.
*
5The A/C amplifier memorizes the trouble code of the respective malfunction when it occurs
for period of time indicated in the brackets.
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±21
Page 22 of 2543
Step No.
Conditions
Blower
MotorAir Flow
ventAir Inlet
damper
Set
Temperature
°C (°F)
Magnetic
clutchAir mix
damper
ACTUATOR CHECK
1. After entering the sensor check mode, press the R/F switch.
2. Turn the temperature set dial and change it to step operation.
Each time the dial is turned, the actuator operation changes
by 1 step.
HINT:
wCheck the change of actuator operation visually and by
hand.
wTo cancel the check mode, press the OFF switch. AC±22
± AIR CONDITIONING SYSTEMTROUBLESHOOTING
Page 23 of 2543
ConditionStandard ValueSymbolTerminal
No.Tester
ConnectionWiring
Color
A C AMPLIFIER TERMINAL STANDARD VALUE
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±23
Page 24 of 2543
Terminal
No.SymbolTester
ConnectionWiring
ColorConditionStandard Value
* After 15 minutes, ON mode will change to OFF mode automatically. AC±24
± AIR CONDITIONING SYSTEMTROUBLESHOOTING
Page 25 of 2543
±MEMO±
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±25
Page 26 of 2543
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
Page 27 of 2543
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
Page 28 of 2543
CIRCUIT INSPECTION
Blinking Light FACE Room Temperature Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the temperature inside the cabin and sends the appropriate signals to the A/C am-
plifier.
Diagnostic Sensor Check Detecting Condition
Open or short in room temperature sensor circuit.
Trouble Area
Room temperature sensor
Harness or connector between room temperature
sensor and A/C amplifier
A/C amplifier
AC±28± AIR CONDITIONING SYSTEMTROUBLESHOOTING
Page 29 of 2543
INSPECTION PROCEDURE
Proceed to next circuit inspection shown on matrix
chart (See page AC±26). However, if the light is still
blinking, check and replace A/C amplifier.
(See page IN±30).(See Page IN±30).
Remove A/C amplifier with connectors still con-
nected.
Check voltage between terminals TR and SG of A/C amplifier connector.
Check room temperature sensor.
Check harness and connector between A/C amplifier and room
temperature sensor (See page
IN±30).
Replace room temperature sensor.
Repair or replace harness or connector.
Check and replace A/C amplifier.
1. Turn ignition switch ON.
2. Measure voltage between terminal TR of SG
of A/C amplifier connector at each temperature.
1. Remove instrument panel.
2. Disconnect room temperature sensor connector.
Check resistance between terminals 1 and 2 of room
temperature sensor connector.
Resistance:
at 25°C (77°F): 1.6 ~ 1.8 k
HINT: As the temperature increases, the voltage decreases
gradually.
Voltage:
at 25°C (77°F): 1.8 ~ 2.2 V
at 40°C (104°F): 1.2 ~ 1.6 V
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±29
Page 30 of 2543
CIRCUIT DESCRIPTION
This sensor detects the ambient temperature and sends the appropriate signals to the A/C amplifier.
Diagnostic Sensor Check Detecting Condition
Open or short in ambient temperature sensor circuit.
Trouble Area
Ambient temperature sensor
Harness or connector between ambient tempera±
ture sensor and A/C amplifier
A/C amplifier
Blinking Light B L Ambient Temperature Sensor Circuit
AC±30± AIR CONDITIONING SYSTEMTROUBLESHOOTING