1995 TOYOTA SUPRA display

Diagnosis Inspection (Test Mode)
Compared to the normal mode, the test mode has an in-
creased sensing ability to detect malfunctions.
It can also detect malfunctions in the starter signal circuit, the
IDL contact signal of the throttle position sensor, air condi-
tioning signal and park/neutral position switch signal.
Furthermore, the same diagnostic items which are detected
in the normal mode can also be detected in the test mode.
DIAGNOSTIC TROUBLE CODE CHECK
1. Initial conditions.
(a) Battery voltage 11 V or more
(b) Throttle valve fully closed
(c) Transmission in neutral position
(d) Air conditioning switched OFF
2. Turn ignition switch OFF
3. Using SST, connect terminals TE2 and E1 of the data link
connector 2.
SST 09843±18020
4. Turn ignition switch ON.
HINT:
wTo confirm that the test mode is operating, check that the
malfunction indicator lamp flashes when the ignition
switch is turned to ON.
wIf the malfunction indicator lamp does not flash, proceed
to troubleshooting of the TE2 terminal circuit on page
EG±484.
5. Start the engine.
6. Simulate the conditions of the malfunction described by the
customer.
7. After the road test, using SST, connect terminals TE1 and E1
of the data link connector 2.
SST 09843±18020
8. Read the diagnostic trouble code on malfunction indicator
lamp on the telltale light RH (See page EG±385).
9. After completing the check, disconnect terminals TE1, TE2
and E1, and turn off the display.
HINT:
wThe test mode will not start if terminals TE2 and E1 are
connected after the ignition switch is turned ON.
wWhen the engine is not cranked, diagnostic trouble
codes º43º (Starter signal) output, but this is not
abnormal.
wWhen the automatic transmission shift lever is in the ºDº,
º2º, ºLº or ºRº shift position, or when the air conditioning
is on or when the accelerator pedal is depressed, code
º51º (Switch condition signal) is output, but this is not
abnormal. EG±386
± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

If a malfunction code is displayed during the diagnostic trouble code check in test mode, check the circuit for
that code listed in the table below (Proceed to the page given for that circuit).
EG±409
EG±412
EG±413
EG±418
EG±419
Malfunction
Indicator
Lamp*
1Trouble Area
Normal
ModeTest
Mode
See pageMemory*2
ON
ON
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
ON
ON
ON
ON

Open or short in NE, G circuit

Distributor

Open or short in STA circuit

ECM

Open or short in NE circuit

Distributor

ECM

Open or short in NE circuit

Distributor

ECM

Open or short in IGT or IGT circuit from igniter to ECM

Igniter

ECM

ECM

Open or short in heater circuit of main heated oxygen
sensor (Fr)

Main heated oxygen sensor (Fr) heater

ECM

(Main heated*3) oxygen sensor (Fr) circuit

(Main heated*3) oxygen sensor (Fr)
*1, 2, 3: See page EG±396
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±389

DTC
No.Number of
MIL BlinksCircuitDiagnostic Trouble Code Detecting Condition
EGR System
Malfunction
Fuel Pump
Control Signal
Switch Condition
Signal
(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 ªRº, ªDº, ª2º, or ªLº position)
(3) A/C switch ON
(3) Open or short in diagnostic signal line (DI) of fuel pump
ECU with engine speed 1,000 rpm or less
(2 trip detection logic)*
4
(2) Open in input circuit of fuel pump ECU (FPC) with engine
speed 1,000 rpm or less
(2 trip detection logic)*
4
(1) Open or short in fuel pump circuit for 1 sec. or more with
engine speed 1,000 rpm or less
(2 trip detection logic)*
4
EGR gas temp. is 70°C (158°F) or less for 1 Ð 4 min. under
conditions (a) and (b):
(2 trip detection logic)*
4
(a) Engine Coolant temp.: 63°C (145°F) or more
(b) EGR operation possible (Example A/T in 3rd speed (5th for
M/T),
A/C ON, 96 km/h (60 mph), Flat road)
*1: ºONº displayed in the diagnostic mode column indicates that the Malfunction Indicator Lamp is lit up when
a malfunction is detected. ºOFFº indicates that the ºCHECKº does not light up during malfunction
diagnosis, even if a malfunction is detected. ºN.A.º indicates that the item is not included in malfunction
diagnosis.
*2: º
º 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.
*3: Only for California specification vehicles. EG±396
± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

BASIC INSPECTION
In many cases, by carrying out the basic engine check shown in the following flow chart, the location causing
the problem can be found quickly and efficiently. Therefore, use of this check is essential in engine trouble-
shooting.
If there is a problem, and a normal code is displayed, proceed to the matrix chart of problem symptoms on page
EG±408. Make sure that every likely cause of the problem is checked.
EG±408.
Is battery positive voltage 11 V or more when engine is stopped?
Is engine cranked?
Does engine start?
Check air filter.
Charge or replace battery.
Proceed to matrix chart of problem symptoms
on page EG±408.
Repair or replace.
Remove air filter.
Visually check that the air filter is not excessive dirty or
oily.
If necessary, clean the air filter with compressed air. First
blow from inside thoroughly, then blow from outside of
the air filter.
EG±400± ENGINE2JZ±GE 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. 2.0 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 ~ 25 steps
Step increases
Step increases
Approx. 125 steps
 ENGINE SPEED RPM kept stable (Comparison with tachometer) No great changes 
 VA F
 
 Engine idling at normal operating temp.*1
Increase engine speed
 
 Approx. 35 ms
Gradually decreases
 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*5 Engine idling at normal operating temp. 2.50 + 1.25 V*3
 TARGET A/FR*6 Engine idling at normal operating temp. 2.50 + 1.25 V*3
 A/F FB LEFT*5 RPM stable at 2500 rpm with normal operating temp. ON
 A/F FB RIGHT*6 RPM stable at 2500 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
 O X L*5 RPM stable at 2500 rpm with normal operating temp. RICH LEAN is repeated O X R*6 RPM stable at 2500 rpm with normal operating temp. RICH LEAN is repeated
*1: If the engine coolant temp. sensor circuit is open or shorted, the ECM assumes an engine coolant temp.
value of 80
°C (176°F).
*
2: When feedback control is forbidden, 0 V is displayed.
*
3: A/T only
*
4: Oxygen sensor (Front)
*
5: Oxygen sensor (Rear)
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±407

INSPECTION PROCEDURE
(See page EG±404)
Check voltage between terminals KS and E1 of engine control module
connector.
Connect SST (check harness ªAº).
(See page EG±404)
SST 09990±01000
Measure voltage between terminals KS and E1 of
engine control module connector while engine is
cranked.
Voltage: 2.0 Ð 4.0 V
(Neither 0 V nor 5 V)
INSPECTION USING OSCILLOSCOPE
Check for open and short in harness and connector between engine control
module and volume air flow meter (See page
IN±30).
When diagnostic trouble code 31 is displayed,
check and replace engine control module.
Repair or replace harness or connector.

During cranking or idling, measure waveform
between terminals KS and E1 of engine control
module.
HINT: The correct waveform is as shown
.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±439

DTC 41 Throttle Position Sensor Circuit
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle
body and detects the throttle valve opening angle. When
the throttle valve is fully closed, the IDL contacts in the
throttle position sensor are on, so the voltage at the ter-
minal IDL of the ECM becomes 0 V. At this time, a voltage
of approximately 0.7 V is applied to the terminal VTA of
the ECM. When the throttle valve is opened, the IDL con-
tacts go off and thus the power source voltage of approx-
imately 12 V in the ECM is applied to the terminal IDL of
the ECM. The voltage applied to the terminal VTA of the
ECM increases in the proportion to the opening angle of
the throttle valve and becomes approximately 3.2 ± 4.9
V when the throttle valve is fully opened. The ECM
judges the vehicles driving conditions from these signals
input from the terminals VTA and IDL, and uses them as
one of the conditions for deciding the air±fuel ratio
correction, power increase correction and fuel±cut con-
trol etc.
Diagnostic Trouble Code Detecting ConditionDTC No.Trouble Area

Open or short in throttle position sensor
circuit

Throttle position sensor

ECM
Open or short in throttle position sensor circuit
for 0.5 sec. or more
HINT:

When the connector for the throttle position sensor is disconnected, diagnostic trouble code 41 is not displayed.
Diagnostic trouble code 41 is displayed only when there is an open or short in the VTA signal circuit of the throttle
position sensor.
EG±442± ENGINE2JZ±GE ENGINE TROUBLESHOOTING

INSPECTION PROCEDURE
HINT: If diagnostic trouble code 52 is displayed, check No.1 knock sensor (for front side) circuit.
If diagnostic trouble code 55 is displayed, check No.2 knock sensor (for rear side) circuit.
If diagnostic trouble code 53 is displayed, replace engine control module.
(See page
EG±404)
Check continuity between terminals KNK1, KNK2 of engine control module
connector and body ground.
(1) Connect SST (check harness ªAº).
(See page EG±404)
SST 09990±01000
(2) Disconnect the engine control modulecon±
nectors.
Measure resistance between terminals KNK1,
KNK2 of engine control module connector and
body ground.
Resistance: 1 M
or higher
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±451