Page 11 of 2543
USE OF MANIFOLD GAUGE SET
MANIFOLD GAUGE SET INSTALLATION
1. CONNECT CHARGING HOSES TO MANIFOLD GAUGE
SET
Tighten the nuts by hand.
CAUTION: Do not connect the wrong hoses.
2. CONNECT QUICK CONNECTORS TO CHARGING HOSES
Tighten the nuts by hand.
3. CLOSE BOTH HAND VALVES OF MANIFOLD GAUGE
SET
4. REMOVE CAPS FROM SERVICE VALVES ON
REFRIGERANT LINE
5. CONNECT QUICK CONNECTORS TO SERVICE VALVES
HINT: Push the quick connector onto the service valve, then
slide the sleeve of the quick connector downward to lock it.
MANIFOLD GAUGE SET REMOVAL
1. CLOSE BOTH HAND VALVES OF MANIFOLD GAUGE
SET
2. DISCONNECT QUICK CONNECTORS FROM SERVICE
VALVES ON REFRIGERANT LINE
HINT: Slide the sleeve of the quick connector upward to un-
lock the connector and remove it from the service valve.
3. INSTALL CAPS TO SERVICE VALVES ON REFRIGERANT
LINE
± AIR CONDITIONING SYSTEMUSE OF MANIFOLD GAUGE SETAC±11
Page 17 of 2543
Warning for A/C compressor lock
If compressor lock occurs during air conditioning operation,
the [A/C] switch indicator on the air conditioning control as-
sembly starts blinking.
When this occurs, check for compressor lock using panel
diagnosis check then proceed to inspect the circuit or the
component.
Compressor lock sensor circuit " page AC±38
LIST OF OPERATION METHODS
By operating each of the air conditioning control switches as shown in the diagram below, it is possible to
enter the diagnosis check mode.
Indicator Check
Diagnostic
Sensor Check
(continuous operation)
Diagnostic
Sensor Check
(stepped operation)
Cancel check mode and can start
conditioning control
Actuator Check
(continuous
operation)
Turn ignition switch ON with AUTO and
switches held down.
If both Auto switch and switch are
not pressed at the same time.
: Indicates a switch operation
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±17
Page 18 of 2543
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
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 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 38 of 2543
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
CompressorCompressor 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
Page 39 of 2543
INSPECTION PROCEDURE
(See page AC±26).
(See page IN±30).
Repair or replace harness or connector.
Replace compressor lock sensor.
Check for open and short harness and connector between A/C amplifier
and room temperature sensor (See page
IN±30).
Check compressor lock sensor.
Check compressor.
Adjust drive belt tension or repair compressor.
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.
Disconnect compressor lock sensor connector
Measure resistance between terminals 1 and 2 of
compressor lock sensor connector.
Resistance: at 20°C (68°F): 160 ~ 210
(1) Check compressor drive belt tension.
(2) Check the compressor does not lock during operation with engine started and blower
switch
and A/C switch ON.
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±39
Page 68 of 2543
Repair or replace A/C control assembly.
Check and replace A/C amplifier.
SwitchCheck result
ON
OFFNo continuity
Continuity
Remove A/C control assembly and disconnect con
nectors.
Check continuity of switch circuit in A/C control assembly.
1. Push the control switch on or Off.
2. Check continuity between terminals as follows.
FAND ± : Turn fan speed dial counterclockwise.
FAND + : Turn fan speed dial clockwise.
AC±68± AIR CONDITIONING SYSTEMTROUBLESHOOTING
![TOYOTA SUPRA 1995 Service Repair Manual Warning for A/C compressor lock
If compressor lock occurs during air conditioning operation,
the [A/C] switch indicator on the air conditioning control as-
sembly starts blinking.
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If compressor lock occurs during air conditioning operation,
the [A/C] switch indicator on the air conditioning control as-
sembly starts blinking.
When this occurs, ch")
