1995 TOYOTA SUPRA display

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

INSPECTION PROCEDURE
AC±22).
Check and replace A/C amplifier.
Repair or replace harness or connector.
Check for open and short in harness and connector between A/C amplifier and air outlet damper control
servo motor, air outlet damper control servo motor and battery, air outlet damper control servo motor
and body ground (See page IN±26).
Replace air outlet servo motor.
Check air outlet damper control servo motor.
Proceed to next circuit inspection shown on matrix
chart (See page AC±26).
Actuator check.
Turn the temp. dial and check the condition of air flow.

The mode changes with the change in the tempera-
ture display as shown in the table.
The lever moves smoothly to DEF position.
The lever moves smoothly to FACE position.
Connect positive (+) lead to terminal 1 and negative
(±) lead to terminal 2.
Connect negative (±) lead to terminal 1 and positive
(1) lead to terminal 2.
1. Remove instrument panel.
2. Remove the air outlet damper control servo motor
assembly.
1. Set to the actuator check mode (see page AC±22).
2. Turn the temp. dial and change to step operation
.
± AIR CONDITIONING SYSTEMTROUBLESHOOTINGAC±51

The trouble code is indicated, as shown in the illustration at
left (Diagnostic trouble code º42º is
shown as an example).
HINT: When 2 or more trouble codes are stored in memory,
the lower±numbered code is displayed first. If no diagnostic
trouble code is output, or if a diagnostic trouble code is output
even though no diagnostic trouble code output operation is
performed, check the TE 1 terminal circuit on page AT1±93.
DIAGNOSTIC TROUBLE CODE CHECK
BY USING TOYOTA HAND±HELD
TESTER
1. Hook up the TOYOTA hand±held tester to the DLC2.
2. Read the diagnostic trouble codes by following the prompts
on the tester screen.
Please refer to the TOYOTA hand±held tester operator's
manual for further details.
CANCELING DIAGNOSTIC TROUBLE
CODE
After repair of the trouble area, the diagnostic trouble code
retained in the ECM memory must be canceled out by remov-
ing the EFI fuse for 10 seconds or more, with the ignition
switch OFF.
Check that the normal code is output after connecting the
fuse.
ECM TERMINALS STANDARD VALUE
ECM TERMINAL VALUES
MEASUREMENT BY USING TOYOTA BREAK±OUT ±BOX
AND TOYOTA HAND±HELD TESTER
1. Hook up the TOYOTA break±out±box and TOYOTA
hand±held tester to the vehicle.
2. Read the ECM input/output values by following the prompts
on the tester screen.
HINT: TOYOTA hand±held tester has a ºSnapshotº function.
This records the measured values and is effective in the diag-
nosis of intermittent problems.
Please refer to the TOYOTA hand±held tester / TOYOTA
break±out box operator's manual for further details.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±35

DTC
No.Blinking
PatternCircuitDiagnostic Trouble Code Detection Condition
38
42
Either (a) or (b) are detected for 0.5 sec. or more.
(a) Temperature sensor resistance less than 79 
(b) After the engine has been operating for 15 minutes or more,
the resistance at the temperature sensor is more than 156 k
All conditions below are detected 500 times or more continuously.
(2 trip detection logic) *3
(a) No No. 1 vehicle speed sensor signal in 16 pulses of No. 2
vehicle speed sensor signal.
(b) Vehicle speed: 9 km/h (5.6 mph) or more for 4 secs. or more.
(c) Park/neutral position switch: OFF (Other than P or N position)
A/T fluid
temp.
sensor
No. 1 vehicle
speed sensor
No. 2 vehicle
speed sensor
All conditions below are detected 500 times or more continuously.
(2 trip detection logic) *3
(a) No No. 2 vehicle speed sensor signal in 4 pulses of No. 1
vehicle speed sensor signal.
(b) Vehicle speed: 9 km/h (5.6 mph) or more for 4 secs. or more.
(c) Park/neutral position switch: OFF (Other than P or N position)
No. 1
solenoid
valve
(1) Solenoid resistance of 8 or less is detected (*) 8 times or
more when No. 1 solenoid is energized.
(2) Solenoid resistance of 100 k or more is detected (*) 8 times
or more when No. 1 solenoid is not energized.
(*) If the above failures are detected less than 8 times, the ECM
memorizes the malfunction code but the O/D OFF indicator
light does not blink.
No. 2
solenoid
valve
(1) Solenoid resistance of 8 or less is detected (*) 8 times or
more when No. 2 solenoid is energized.
(2) Solenoid resistance of 100 k or more is detected (*) 8 times
or more when No. 2 solenoid is not energized.
(*) If the above failures are detected less than 8 times, the ECM
memorizes the malfunction code but the O/D OFF indicator
light does not blink.
Lock±up
solenoid
valve
(a) Solenoid resistance is 8 or lower (short circuit) when
solenoid energized.
(b) Solenoid resistance is 100 k or higher (open circuit) when
solenoid is not energized.
(*) ECM memorizes diag. trouble code 64 if above (a) or (b)
condition is detected once or more, but ECM does not start
O/D OFF indicator light blinking.
61
62
63
64
DIAGNOSTIC TROUBLE CODE CHART
If a diagnostic trouble code is displayed during the diagnostic trouble code check, check the circuit listed
for that code in the table below and proceed to the page given. AT1±52
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

MATRIX CHART OF PROBLEM SYMPTOMS
If a normal code is displayed during the diagnostic trouble code check but the trouble still occurs, check
the circuits for each symptom in the order given in the charts on the following pages and proceed to the
page given for troubleshooting.
The Matrix Chart is divided into 3 chapters.
Chapter 1: Electronic Circuit Matrix Chart
Chapter 2: On±vehicle Repair Matrix Chart
Chapter 3: Off±vehicle Repair Matrix Chart
When troubleshooting, check Chapter 1 first. If instructions are given in Chapter 1 to proceed to Chapter
2 or 3, proceed as instructed.
1. If the instruction ºProceed to next circuit inspection shown on matrix chartº 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.
2. If the trouble still occurs even though there are no abnormalities in any of the other circuits, then check or
replace the ECM.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±57

Jack up the vehicle.
Remove the oil pan.
Disconnect the solenoid connector.
Measure resistance between solenoid connector
and solenoid body.
Resistance: 10 ± 16

Connect positive (+) lead to terminal of solenoid
connector, negative (±) lead to solenoid body.
Check No. 1, No. 2 solenoid valves.
When battery positive voltage is supplied to
the solenoid valves, check that the solenoid
valves open.
Replace solenoid valve.
Electrical Check
Repair or replace harness or connector.
Check harness and connector between ECM and solenoid (See page IN±30).
Proceed to next circuit inspection shown on matrix chart
(See page AT1±58). However, when diagnostic trouble
code 62 or 63 is displayed, check and replace ECM.
Applying 490 kPa (5 kgf/cm2, 71 psi) of com-
pressed air, check that the solenoid valves do
not leak air.
Remove the oil pan.
Remove the No. 1 and No. 2 solenoid valves.
The solenoid makes an operating noise.
Mechanical Check
INSPECTION PROCEDURE
AT1±74± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING