1986 TOYOTA SUPRA engine coolant

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

(See page EG±510)
(1) Connect SST (check harness ªAº).
(See page EG±510)
(2) Turn ignition switch ON
Measure voltage between terminals THW and
E2 of engine control module connector.
Check voltage between terminals THW and E2 of engine control module
connector.
Check for intermittent problems.
(See page EG±505)
Disconnect the engine coolant temp. sensor con-
nector.
Measure resistance between terminals.
Resistance is within Acceptale Zone on chart.
Check engine coolant temp. sensor.
Replace engine coolant temp. sensor.
Repair or replace harness or connector.
Check and replace engine control module.
Check for open and short in harness and connector between engine control
module and engine coolant temp. sensor (See page IN±30).
INSPECTION PROCEDURE
HINT: If diagnostic trouble codes º22º (engine coolant temperature sensor circuit), º24º (intake air temperature
sensor circuit) and º41º (throttle position sensor circuit) are output simultaneously, E2 (sensor ground)
may be open.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±531

DTC 24 Intake Air Temp. Sensor Circuit
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the mass air flow meter and senses the intake air temperature. The struc-
ture of the sensor and connection to the ECM is the same as in the engine coolant temp. sensor shown on page
EG±530.
If the ECM detects the diagnostic trouble code º24º, it operates the fail safe function in which the intake air tem-
perature is assumed to be 20°C (68°F).
 
 DTC No.
 
 Diagnostic Trouble Code Detecting Condition
 


Trouble Area
 
 
 
 
24
 
 
 
 
Open or short in intake air temp. sensor circuit
for 0.5 sec. or more
 





Open or short in intake air temp. sensor

Circuit

Intake air temp. sensor

ECM
EG±532± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

(See page EG±510)
(1) Connect SST (check harness ªAº).
(See page EG±510)
SST 09990±01000
(2) Turn ignition switch ON
Measure voltage between terminals THW and E2
of engine control module connector.
Check voltage between terminals THA and E2 of engine control module
connector.
Check for intermittent problems.
(See page EG±505)
Disconnect the mass air flow meter connector.
Measure resistance between terminals 3 and 4
of mass air flow meter connector.
Resistance is within Acceptable Zone on chart.
Check intake air temp. sensor.
Check for open and short in harness and connector between engine
control module and intake air temp. sensor (See page IN±30)
Replace intake air temp. sensor (Replace
mass air flow meter).
Repair or replace harness or connector.
Check and replace engine control module.
INSPECTION PROCEDURE
HINT: If diagnostic trouble codes º22º (engine coolant temperature sensor circuit), º24º (intake air temperature
sensor circuit) and º41º (throttle position sensor circuit) are output simultaneously, E2 (sensor ground)
may be open.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±533