1995 TOYOTA SUPRA engine coolant

DTC
No.
Number of
MIL BlinksCircuitDiagnostic Trouble Code Detecting Condition
No starter signal to ECM
Open or short in throttle position sensor circuit for 0.5 sec. or
more
Engine control computer (for knock control) malfunction at
engine speed between 650 rpm and 5,200 rpm
(c) Park/neutral position switch: OFF
(d) Stop light switch: OFF
(a) No. 1 vehicle speed signal: 0 km/h (mph)
(b) Engine speed: 3,000 or more
All conditions below are detected continuously for 8 sec. or more:
(a) No. 1 vehicle speed signal: 0 km/h (mph)
(b) Engine speed: Between 1,500 rpm and 4,000 rpm
All conditions below are detected continuously for 8 sec. or more:
(c) Engine coolant temp.: 80°C (176°F) or more
(d) Load driving
Open or short in sub±throttle position sensor circuit for 0.5 sec.
or more
No No.2 knock sensor signal to ECM for 4 crank revolutions
with engine speed between 2,050 rpm and 5,950 rpm
No No.1 knock sensor signal to ECM for 4 crank revolutions
with engine speed between 2,050 rpm and 5,950 rpmKnock Sensor
Signal
(front side)
Knock Sensor
Signal
(rear side)
Knock Control
Signal
Sub±Throttle
Position Sensor
Signal
No. 1 Vehicle
Speed Sensor
Signal
(for A/T)
No. 1 Vehicle
Speed Sensor
Signal
(for M/T)
Starter Signal
Throttle Position
Sensor Signal
EG±500± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

DTC
No.
Number of
MIL BlinksCircuitDiagnostic Trouble Code Detecting Condition
(a) Engine coolant temp.: 60°C (140°F) or more
(2 trip dectection logic)*3
(2 trip dectection logic)*3
(2 trip dectection logic)*3
EGR gas temp. and intake air temp. are 60°C (140°F) or less
for A/T, 55°C (131°F) or less for 1 ~ 4 min. under conditions
(a) and (b):
Fuel Pump
Control Signal
(2 trip dectection logic)*3
(b) EGR operation possible (Example A/T in 3rd speed (5th for
M/T), A/C ON, 96 km/h (60 mph), Flat road)
Switch Condition
Signal
EGR System
Malfunction
(2) Open in input circuit for 1 sec. or more with engine speed
1,000 rpm or less
(1) Open or short in fuel pump circuit for 1 sec. or more with
engine speed 1,000 rpm or less
(3) Open or short in diagnostic signal line (DI) fuel pump ECU
with engine speed 1,000 rpm or less
(1) 3 sec. or more after engine starts, with closed throttle posi±
tion switch OFF (IDL1)
(2) Park/neutral position switch: OFF
(Shift position in ''R'', ''D'', ''2'', or ''L'' position)
(3) A/C switch ON
*1: ºONº displayed in the diagnostic mode column indicates that the Malfunction Indicator Lamp is lit up when
a malfunction is defected. ºOFFº indicates that the ºCHECKº does not light up during malfunction diag±
nosis, even if a malfunction is detected. ºN.A.º indicates that the item is not included in malfunction diag±
nosis.
*2: ºº in the memory column indicates that a diagnostic trouble code is recorded in the ECM memory when
a malfunction occurs. ºXº indicates that a diagnostic trouble code is not recorded in the ECM memory even
if a malfunction occurs. Accordingly, output of diagnostic results in normal or test mode is done with the
IG switch ON. EG±502
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

G, NE signal circuit (No.2)
Engine coolant temp. sensor
circuit
Intake air temp. sensor circuit
Throttle position sensor
circuit
Sub±throttle position sensor
circuit
CircuitDTC
CHECK FOR INTERMITTENT PROBLEMS
As described in the preceding paragraph, abnormality detection
ability in the test mode is increased compared to that in the normal
mode, so that when intermittent problems occur in the ECM signal
circuits (G1, G2, NE, THW, THA, VTA1, VTA2) shown in the table
below, the appropriate diagnostic trouble code is output.
Accordingly, when the diagnostic trouble codes shown in the table
opposite (13, 22, 24, 41, 47) are output during the diagnostic
trouble code check, and inspection of the appropriate circuits re-
veals no abnormality, check for intermittent problems as described
below.
By checking for intermittent problems, the place where intermittent
problems are occurring due to poor contacts can be isolated.
CLEAR DIAGNOSTIC TROUBLE CODES
See page EG±493.
SET TEST MODE
1. With the ignition switch OFF, using SST, connect the
terminals TE2 and E1 of the data link connector 2.
SST 09843±18020
2. Start the engine and check to see the malfunction indicator
lamp goes off.
PERFORM A SIMULATION TEST
Using the symptom simulation (See page IN±24), apply vibration
to and pull lightly on the wire harness, connector or terminals in the
circuit indicated by the malfunction code.
In this test, if the malfunction indicator lamp lights up, it indicates
that the place where the wire harness, connector or terminals be-
ing pulled or vibrated has faulty contact. Check that point for loose
connections, dirt on the terminals, poor fit or other problems and
repair as necessary.
HINT: After cancelling out the diagnostic trouble code in memory
and set the test mode, if the malfunction indicator lamp does not
go off after the engine is started, check thoroughly for faulty con-
tacts, etc., then try the check again, if the malfunction indicator
lamp still does not go off, check and replace ECM.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±505

STANDARD VALUE OF ECM TERMINALS
Always
IG switch ON
IG switch ON
IG switch ON and apply vacuum to the
throttle opener Throttle valve fully closed
IG switch ON
Main or sub±throttle valve fully closed
Idling, Intake air temp. 0°C (32°F) to 80°C
(176°F)
IG switch ON Throttle valve fully open
IG switch ON Sub±throttle valve fully closed
IG switch ON
Main or sub±throttle valve fully closed
IG switch ON Sub±throttle valve fully open
IG switch ON
Main or sub±throttle valve fully open
Idling, Engine coolant temp. 60°C (140°F) to
120°C (248°F)
Cranking
IG switch ON
Idling
IG switch ON
IG switch ON
Idling
Idling
Idling
Idling
Idling
IG switch ON
IG switch ON
IG switch ON
Pulse generation
Pulse generation
Pulse generation
Pulse generation
Pulse generation
Symbols (Terminals No.)STD Voltage (V)Condition
(See page EG±583)
(See page EG±521)
(See page EG±521)
(See page EG±517)
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±511

 Symbols (Terminals No.) STD Voltage (V) Condition
 EGR (B75) E01 (B80) Below 2.0 Idling
 EGR (B75)±E01 (B80) 9 ~ 14 Engine speed at 3,500 rpm
 VG (B66)±E21 (B28) 0.7 ~ 1.7 Idling
 
 
ISC1 (B35), ISC2 (B34)
Ð E01 (B80)
ISC3 (B33), ISC4 (B32) 
 
Pulse generation
(See page EG±586) 
 Idling when A/C switch ON or OFF
 
VF1 (B29)±E1 (B69) 

1.8 ~ 3.2 

Maintain engine speed at 2,500 rpm for 2
minutes after warming up then return to Idling
 
 OX1 (B48), OX2 (B47)±E1 (B69)
 
 Pulse generation
(See page EG±529)
 
 Maintain engine speed at 2,500 rpm for 2
minutes after warming up
 
HT1 (B71) HT2 (B72) E01 (B80)
 Below 3.0 Idling HT1 (B71), HT2 (B72)±E01 (B80) 9 ~ 14 IG switch ON 
 KNK1 (B50), KNK2 (B49)±E1 (B69)
 
 Pulse generation
(See page EG±563) 
 Idling
 
 
NSW (B76) E1 (B69)
 
 9 ~ 14
 
 IG switch ON
Other shift position in ºPº, ºNº position
 
 
NSW (B76)±E1 (B69) 
 0 ~ 3.0
 
 IG switch ON
Shift position in ºPº, ºNº position
 
 SP1 (A2)±E1 (B69)
 
 
Pulse generation
(See page EG±556) 
 
IG switch ON
Rotate driving wheel slowly
 TE1 (A20)±E1 (B69) 9 ~ 14 IG switch ON
 TE2 (A19)±E1 (B69) 9 ~ 14 IG switch ON
 W (A6)±E1 (B69) 9 ~ 14 Idling
  0 ~ 3.0 IG switch ON
 OD1 (A12)±E1 (B69) 9 ~ 14 IG switch ON
 A/C (A34)±E1 (B69) 7.5 ~14 A/C switch OFF
  0 ~ 1.5 A/C switch ON (At idling)
 ACMG (A23)±E1 (B69) 0 ~ 3.0 A/C switch ON (At idling)
  9 ~ 14 A/C switch OFF
 FPU (B73)±E01 (B80) 9 ~ 14 IG switch ON
  Below 2.0 Restarting at high engine coolant temp.
 ELS (A15)±E1 (B69) 7.5 ~ 14 Defogger switch and taillight switch ON
  0 ~ 1.5 Defogger's switch and taillight switch OFF
 VSV1 (B40)±E1 (B69) Below 3.0 Immediately after racing
  9 ~ 14 Idling
 VSV2 (B39)±E1 (B69) Below 3.0 For 2 sec. after IG switch ON to OFF
  9 ~ 14 Idling
 VSV3 (B38)±E1 (B69) 9 ~ 14 Idling
 
 
 PMC (B60)±E1 (B69)
 
 
 
Below 3.0
 
 
 
Idling (for M/T)
Idling and shift position ºPº, ºNº position
(for AT)
 

PMC (B60)±E1 (B69)
 

9 ~ 14 

Idling and other shift position ºPº, ºNº
position (for A/T))
 
PM1 (B62)±E2 (A65)
 
2.3 ~ 3.0
 
IG switch ON 
 
 
 1.8 ~ 2.4
 
 IG switch ON and apply vacuum 26.7 kPa
(200 mmHg, 7.9 in Hg)
EG±512± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

REFERENCE VALUE OF ECM DATA
HINT: ECM data can be monitored by TOYOTA hand±held
tester.
1. Hook up the TOYOTA hand±held tester to DLC2.
2. Monitor ECM data by following the prompts on the tester
screen.
Please refer to the TOYOTA hand±held tester operator's manual
for further details.
REFERENCE VALUE 
 Item
 
 Inspection condition
 
 Reference value
 
 INJECTOR 
 
Engine cold to hot
Engine idling at normal operating temp.*1
 
 
Gradually decreases
Approx. 1.8 msec.
 IGNITION Increase engine speed Gradually increases
 
 
 
 
IAC STEP #
 
 
 
 
Engine idling at normal operating temp..*1
A/C switch ON
A/T shifting in ºDº position
Ignition switch ON (Engine off)
 
 
 
 
20 ~ 30 steps
Step increases
Step increases
Approx. 125 steps`
 ENGINE SPEED RPM kept stable (Comparison with tachometer) No great changes
 
 MAF
 
 Engine idling at normal operating temp..*1
Increase engine speed
 
 Approx. 3.8 g/s
Gradually increases
 ECT Engine at normal operating temp. 75±95°C (185±203°F).*2 
 
 THROTTLE
 
 
 
Closed throttle position
Wide open throttle
From closed throttle position to wide open throttle
 
 
 
Below 5°
Above 70°
Gradually increases 
 
 
VEHICLE SPD
 
 
 
During driving
(Comparison with speedometer)
 
 
 
No large differences
 TARGET A/FL Engine idling at normal operating temp. 2.50 + 1.25 V*3
 A/F FB LEFT RPM stable at 2,500 rpm with normal operating temp. ON
 KNOCK FB Depress throttle pedal suddenly during idling ON 
 STA SIGNAL 
 During cranking 
 ON
 CTP SIGNAL Closed throttle position ON
 A/C SIGNAL A/C switch ON ON
 
 PNP SIGNAL.*4 
 
When shifting from ºPº or ºNº position into a position
other than ºPº or ºNº 
 GEAR
 OxL RPM stable at 2,500 rpm with normal operating temp. RICH LEAN is repeated
*1: All accessories and A/C switched OFF
*
2: If the engine coolant temp. sensor circuit is open or shorted, the ECM assumes an engine coolant temp.
value of 80°C (176°F).
*
3: When feedback control is forbidden, 0 V is displayed.
*
4: A/T only
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±513

See page EG±503.
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way
catalytic converter is used, but for most efficient use of the three±way catalytic converter, the air±fuel
ratio must be precisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity
of the stoichiometric air±fuel ratio. This characteristic is used to detect the oxygen concentration in the
exhaust gas and provide feedback to the computer for control of the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the
oxygen sensor informs the ECM of the LEAN condition (small electromotive force: 0 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio the oxygen concentration in the
exhaust gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electro-
motive force: 1 V).
The ECm judges by the electromotive force from the oxygen sensor whether the air±fuel ratio if RICH
or LEAN and controls the injection duration accordingly. However, if malfunction of the oxygen sensor
causes an output of abnormal electromotive force, the ECM is unable to perform accurate air±fuel ratio
control.
The main heated oxygen sensor include a heater which heats the Zirconia element. The heater is con-
trolled by the ECM. When the intake air volume is low (the temperature of the exhaust has is low) current
flows to the heater to heat the sensor for accurate oxygen concentration detection.)
Diagnostic Trouble Code Detecting ConditionDTC No.Trouble Area
(1) Open or short in heater circuit of main heated
oxygen sensor for 0.5 sec. or more.
(2) Main heated oxygen sensor signal voltage is
reduced to be 0.35 V and 0.70V for 60 sec.
under condition (a) ~ (d):
(2 trip detection logic)*1
(a) Engine coolant temp.: Between 80°C
(176°F) and 95°C (203°F)
(b) Engine speed: 1,500 rpm or more
(c) Load driving (Example A/T in
overdrive (5th for M/T), A/C ON, Flat
road, 80 km/h (50 mph))
(d) Main heated oxygen sensor signal
voltage: Alternating above and below
0.45V

Open or short in heater circuit of main heated
oxygen sensor

Main heated oxygen sensor heater

ECM

Main heated oxygen sensor circuit

Main heated oxygen sensor
DTC 21 Main Heated Oxygen Sensor Circuit
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±525

CIRCUIT DESCRIPTION
The engine coolant temperature sensor senses the
coolant temperature. A thermistor built in the sensor
changes its resistance value according to the coolant
temperature. The lower the coolant temperature, the
greater the thermistor resistance value, and the high-
er the coolant temperature, the lower the thermistor
resistance value (See Fig. 1).
The engine coolant temperature sensor is connected
to the ECM (See wiring diagram). The 5 V power
source voltage in the ECM is applied to the engine
coolant temperature sensor from the terminal THW
via a resistor R. That is, the resistor R and the engine
coolant temperature sensor are connected in series.
When the resistance value of th engine coolant tem-
perature sensor changes in accordance with changes
in the coolant temperature, the potential at the termi-
nal THW also changes. Based on this signal, the ECM
increases the fuel injection volume to improve drive-
ability during cold engine operation. If the ECM re-
cords the diagnostic trouble code 22, it operates the
fail safe function in which the engine coolant tempera-
ture is assumed to be 80°C (176°F).
Diagnostic Trouble Code Detecting ConditionDTC No.Trouble Area
Open or short in engine coolant temp. sensor
circuit for 0.5 sec. or more
Open or short in engine coolant temp.
sensor circuit

Engine coolant temp. sensor

ECM
DTC 22 Engine Coolant Temp. Sensor Circuit
EG±530± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING