check engine light TOYOTA SUPRA 1995 Service Owner's Manual

PREPARATION
SST (SPECIAL SERVICE TOOLS)
09843±18020Diagnosis Check Wire
09808±14010Fuel Sender Gauge Tool Assy
09950±50010Puller C Set
RECOMMENDED TOOLS
09082±00050TOYOTA Electrical Tester Set


EQUIPMENT
 
 Voltmeter
 
 
 Ammeter 
 Ohmmeter 
 Test lead 
 Thermometer Engine oil level warning switch, Seat heater
 Syphon Brake fluid level warning switch
 Oil bath Engine oil level warning switch
 Bulb (3.4 W) Fuel sender gauge, Seat belt warning relay Bulb (21 W) Turn signal flasher relay Dry cell battery Fuel sender gauge 
 Heat light
 
 Seat heater
 Torque wrench 
 Masking tape Rear window defogger wire
 Tin foil Rear window defogger wire
SSM (SPECIAL SERVICE MATERIAL)
 

DuPont Paste No. 4817 or
equivalent
 

Rear window defogger
 
 
equivalent 
 
± BODY ELECTRICAL SYSTEMPREPARATIONBE±3

WARNING LIGHTS
 Trouble Parts name (See page)
 
 
 
 
 
Warning lights do not light up
(Except Discharge and Door Open)
 
 
 
 
 
1. Bulb
2. IGN Fuse (BE±6)
3. Ignition Switch (BE±8)
4. Meter Circuit Plate (BE±44)
5. Wire Harness
6. Generator
 
 
 
 
 
 
Brake Warning Light does not light up
 
 
 
 
 
 
1. Bulb
2. Brake Fluid Level Warning Switch (BE±52)
3. Parking Brake Switch (BE±52)
4. Bulb Check Relay
5. Meter Circuit Plate (BE±44)
6. Wire Harness
 
 
 
 
 
Seat Belt Warning Light does not light up
 
 
 
 
 
1. Bulb
2. Seat Belt Buckle Switch (BE±56)
3. Integration Relay (BE±55)
4. Meter Circuit Plate (BE±44)
5. Wire Harness
 
 
 
 
Engine Oil Level Warning Light does not light up
 
 
 
 
1. Bulb
2. Engine Oil Level Switch (BE±51)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
Low Oil Pressure Warning Light does not light up
 
 
 
1. Bulb
2. Low Oil Pressure Warning Switch (BE±51)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
 
 
 
 
Door Open Warning Light does not light up
 
 
 
 
 
 
 
1. Bulb
2. DOME Fuse (BE±5)
3. Door Courtesy Switch (BE±54)
4. Luggage Room Light Switch (BE±28)
5. Integration Relay
6. Meter Circuit Plate (BE±44)
7. Wire Harness
 
 
 
 
Master Warning Light does not light up
 
 
 
 
1. Bulb
2. Telltale Light (BE±48)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
BE±42± BODY ELECTRICAL SYSTEMCOMBINATION METER

ENGINE COOLANT TEMPERATURE
GAUGE INSPECTION
1. INSPECT RECEIVER GAUGE OPERATION
(a) Disconnect the connector from the sender gauge.
(b) Turn the ignition switch ON, check that the receiver gauge
needle indicates COOL.
(c) Ground terminal on the wire harness side connector through
a 3 W test bulb.
(d) Turn the ignition switch ON, check that the bulb lights up and
the receiver gauge needle moves toward the hot side.
If operation is as specified, replace the sender gauge.
Then recheck the system.
If operation is not as specified, measure the receiver gauge
resistance.
2. INSPECT RECEIVER GAUGE RESISTANCE
Measure the resistance between terminals.
HINT: Connect the test leads so that the current from the
ohmmeter can flow according to the chart order.
 Between terminals Resistance (
) 
A±B 
Approx. 229.7
 A±C Approx. 54.0
 B±C Approx. 175.7
If resistance value is not as specified, replace the engine
coolant temperature receiver gauge.
3. INSPECT SENDER GAUGE RESISTANCE
Measure the resistance between terminal and gauge body.
 Temperature °C (°F) Resistance (
)
 50 (122.0) 160 ~ 240
 120 (248.0) 17.1 ~ 21.2
If resistance value is not as specified, replace the engine
coolant temperature sender gauge. BE±50
± BODY ELECTRICAL SYSTEMCOMBINATION METER

LOW OIL PRESSURE WARNING
INSPECTION
1. INSPECT SWITCH
(a) Check that there is continuity between terminal and ground
with the engine stopped.
(b) Check that there is no continuity between terminal and
ground with the engine running.
HINT: Oil pressure should be over 29 kPa (0.3 kgf/ cm
2, 4.3
psi)
If operation is not as specified, replace the switch.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the warning switch and
ground terminal on the wire harness side connector.
(b) Turn the ignition switch ON, check that the warning light lights
up.
If the warning light does not light up, test the bulb or inspect
wire harness.
ENGINE OIL LEVEL WARNING
INSPECTION
1. INSPECT SWITCH
(a) Check that there is continuity between terminal with the
switch in each position.
(b) Heat the switch to above 60°C (140°F) in an oil bath.
(c) Check that there is continuity between terminals with the
switch ON (float up).
(d) Check that there is no continuity between terminals with the
switch OFF (float down).
If operation is not as specified, replace the switch.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the switch.
(b) Ground terminal 1 on the wire harness connector.
(c) Turn the ignition switch ON. Check that the warning light
lights up approximately 40 seconds later.
If the warning light does not light up, inspect bulb or wire har-
ness.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±51

BRAKE FLUID LEVEL WARNING
INSPECTION
1. INSPECT SWITCH
(a) Remove the reservoir tank cap and strainer.
(b) Disconnect the connector.
(c) Check that there is no continuity between terminals with the
switch OFF (float up).
(d) Use syphon, etc. to take fluid out of the reservoir tank.
(e) Check that there is continuity between terminals with the
switch ON (float down).
(f) Pour the fluid back in the reservoir tank.
If operation is not as specified, replace the switch.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the brake fluid warning
switch.
(b) Release the parking brake pedal.
(c) Connect terminals on the wire harness side of the level
warning switch connector.
(d) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or wire har-
ness.
PARKING BRAKE WARNING
INSPECTION
1. INSPECT SWITCH
(a) Check that there is continuity between terminal and switch
body with the switch ON (switch pin released).
(b) Check that there is no continuity between terminal and switch
body with the switch OFF (switch pin pushed in).
If operation is not as specified, replace the switch or inspect
ground point.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the parking brake switch and
the brake fluid warning switch.
(b) Ground terminal on the wire harness side connector.
(c) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or inspect
wire harness. BE±52
± BODY ELECTRICAL SYSTEMCOMBINATION METER

LIGHT FAILURE SENSOR INSPECTION
1. INSPECT SENSOR CIRCUIT
Disconnect the connector from the sensor and inspect the
connector on the wire harness side, as shown.
 
 
 
Tester connection to
terminal number
 
 
 
Condition
 
 
 
Specified condition
 1±Ground Constant Continuity*
 2±Ground Constant Continuity*
 9±Ground Constant Continuity* 
 10±Ground
 
 Constant
 
 Continuity*
 11±Ground Constant Continuity
 12±Ground Constant Continuity*
 3±Ground Light control switch position OFF No Voltage 3±Ground Light control switch position TAIL or HEAD Battery positive voltage 
 4±Ground
 
 Ignition switch position LOCK or ACC
 
 No voltage
 4±Ground Ignition switch position ON Battery positive voltage
 7±Ground Stop light switch position OFF No voltage
 7±Ground Stop light switch position ON Battery positive voltage 
 8±Ground
 
 Engine condition Stop
 
 No voltage
 8±Ground Engine condition Running Battery positive voltage
*: There is resistance because this circuit is grounded
through the bulb.
If circuit is as specified, replace the sensor.
If the circuit is not as specified, inspect the circuits connected
to other parts.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the light failure sensor and
ground terminal 4 on the wire harness side connector.
(b) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or inspect
wire harness.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±53

SYSTEM INSPECTION
1. SETTING OF THE THEFT DETERRENT SYSTEM
Setting Conditions
(a) Close all the doors.
(b) Close the engine hood and luggage compartment door.
(c) Remove the ignition key from the ignition key cylinder.
Setting Operation
When any of the following operations (a) or (c) is done, the theft deterrent indicator light will light up as de-
scribed.
(a) Lock the left or right front door using the key.
(All doors are locked by key±interlinked lock operation)
(b) With the rear doors locked and with one of the front doors locked, lock the other front door without
using the key (keyless door lock).
 
 Elapsed time after operation
 
 Indicator light
  Within about 30 seconds  Lights up
  After about 30 seconds  Blinks *1
*1: 1 sec. on, 1 sec. off
HINT: When the theft deterrent system is set, doors cannot be locked or unlocked with the door lock control
switch and the luggage compartment door cannot be unlocked with the luggage compartment door opener
switch.
2. CANCELLING OF THE THEFT DETERRENT SYSTEM IN THE SET CONDITION
Check if the theft deterrent indicator light is blinking.
Cancelling Operation
When any of the following operation (a), (b), (c) or (d) is done, the theft deterrent system is cancelled and
indicator light will go off.
(a) Unlock the left or right front door using the key.
(b) Insert the ignition key in the ignition key cylinder and turn it to the ACC or ON position.
(This is operative only when the theft deterrent system has never operated.)
(c) Unlock the luggage compartment door with the key. *
1
*1: The theft deterrent system is temporarily cancelled only while the luggage compartment door is
open. Approximately 2 seconds after the luggage compartment door is closed, the theft deterrent
system is reset.
± BODY ELECTRICAL SYSTEMTHEFT DETERRENT AND DOOR LOCK CONTROL SYSTEMBE±121

3. CHECK OF THE THEFT DETERRENT SYSTEM OPERATION.
Check if the theft deterrent indicator light is blinking.
When any of the following operations (a) or (b) is done, the system sounds the horns and theft deterrent
horn and flashes the headlights and taillights for about one minute to alert. At the same time, the system
disconnects the starter motor circuit and locks all doors (if all doors are not locked, the system repeats door
locking operation every 2 seconds during the one minute alert time).
(a) Open the engine hood using the engine hood opener lever.
(b) Unlock any of the front or rear doors without key operation.
4. CANCELLING OF THE THEFT DETERRENT SYSTEM IN OPERATING CONDITION.
The theft deterrent operation can be cancelled when any of the following conditions is met:
 No. Condition Cancelling Operation 
 1
 
 Unlock left or right door with the key.
 
 
 2 Unlock doors with wireless door lock control system. 
 3 Insert key into ignition key cylinder and turn it to ACC or ON position. *2
 4 About 1 minute passes after theft deterrent operation begins. Automatic stop *1
*1: In this case, the theft deterrent system resets in about 2 seconds after if all doors are closed.
*
2: The alarm will be off, but the engine will not operate. To restart the engine, see No.1.
ECU TERMINAL VALUES MEASUREMENT
USING TOYOTA BREAK±OUT±BOX AND
TOYOTA HAND±HELD TESTER
1. Hook up the TOYOTA break±out box and TOYOTA handheld
tester to the vehicle.
2. Read the ECU input/output values by following the prompts
on the hand±held tester screen.
HINT: TOYOTA hand±held tester has a ºShapshotº func-
tion. This records the measured values and is effective in
the diagnosis of intermittent problems.
Please refer to the TOYOTA hand±held tester/TOYOTA
break±out±box operator's manual for further details. BE±122
± BODY ELECTRICAL SYSTEMTHEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

INPUT SIGNAL CHECK
Output Code
1. (a) For check No.1 No.3
Turn the ignition switch on.
(b) For check No.4
Jack up the vehicle.
Start the engine.
2. Turn the control switch to SET/COAST position or RES/ACC
position and hold it down or up (1).
3. Push the main switch on (2).
4. Check that the CRUISE MAIN indicator light blinks twice or
3 times repeatedly.
5. Turn the SET/COAST switch or RES/ACC position off.
6. Operate each switch as listed in the table below.
7. Read the blinking pattern of the CRUISE MAIN indicator light.
8. After performing the check, turn the main switch off.
HINT: When two or more signals are input to the ECU, only
the lowest±numbered code is displayed.
Turn SET/COAST switch ON.
Turn RES/ACC switch ON.
Turn CANCEL switch ON.
Turn stop light switch ON.
(Depress brake pedal)
Turn parking brake switch ON.
(Pull up the parking brake lever).
Turn neutral start switch OFF.
(Shift to EXCEPT D RANGE).
Turn clutch switch OFF.
(Depress clutch pedal)
Drive at 40 km/h (25 mph) or
higher.
Drive at 40 km/h (25 mph) or
below.
SET/COAST switch circuit is
normal.
RES/ACC switch circuit is
normal.
CANCEL switch circuit is
normal.
Stop light switch circuit is
normal.
Parking brake switch circuit
is normal.
Neutral start switch circuit is
normal.
Clutch switch circuit is
normal.
Speed sensor is normal.
DiagnosisOperation MethodCRUISE MAIN Indicator Light
Blinking Pattern
± BODY ELECTRICAL SYSTEMBE±169CRUISE CONTROL SYSTEM

(See page BE±42).
BE±169.
Proceed to next circuit inspection shown on matrix
chart (See page
BE±170).
(1) See input signal check on page BE±169.
(2) Check the indicator light when the parking brake
lever is pulled up.
Check operation of brake warning light.
Check voltage between terminal PKB of cruise control ECU connector and
body ground.
(1) Turn ignition switch ON.
(2) Measure voltage between terminal PKB of cruise
control ECU connector and body ground, when
the parking brake lever is pulled up and released.
Remove cruise control ECU with connectors still con-
nected.
Input signal check.
The indicator light goes off when the parking brake lever
is pulled up.
Check that the brake warning light in the instrument panel comes on when the parking brake lever is
pulled up with the engine running, and the light goes off when the parking brake lever is released.
Check brake warning light circuit
Parking brake lever
Proceed to next circuit inspection shown on matrix
chart (See page
BE±170).
Voltage
Pulled up
Released
Check for open in harness and connector between cruise control ECU and
brake warning light.
Repair or replace harness or connector.
Check and replace cruise control ECU. BE±190
± BODY ELECTRICAL SYSTEMCRUISE CONTROL SYSTEM