1995 TOYOTA SUPRA sensor
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DIAGNOSIS SYSTEM
DESCRIPTION
The ECM contains a built±in self±diagnosis system by which
troubles with the engine signal network are detected and a Mal-
function Indicator Lamp on the instrument panel lights up.
By analyzing various signals as shown in a later table (See page
EG±494) the Engine Control Module (ECM) detects system mal-
functions relating to the sensors or actuators.
In the normal mode, the self±diagnosis system monitors 19 items,
indicated by code No. as shown in EG±494. A malfunction indica-
tor lamp informs the driver that a malfunction has been detected.
The lamp goes off automatically when the malfunction has been
repaired, but the diagnostic trouble code(s) remains stored in the
ECM memory (except for code Nos. 16 and 53). The ECM stores
the code(s) until it is cleared by removing the EFI No. 1 fuse with
the ignition switch OFF.
The diagnostic trouble code can be read by the number of blinks
of the malfunction indicator lamp when TE1 and E1 terminals on
the data link connector 1 or 2 are connected. When 2 or more
codes are indicated, the lowest number (code) will appear first.
In the test mode, 13 items, indicated by code No. as shown in
EG±494 are monitored. If a malfunction is detected in any one of
the systems indicated by code Nos. 13, 21, 22, 24, 25, 26, 27, 35,
41, 47, 71 and 78 the ECM lights the malfunction indicator lamp
to warn the technician that a malfunction has been detected. In
this case, TE2 and E1 terminals on the data link connector 2
should be connected as shown later. (See page EG±492).
In the test mode, even if the malfunction is corrected, the malfunc-
tion code is stored in the ECM memory even when the ignition
switch OFF (except code Nos. 43 and 51). The also applies in the
normal mode. The diagnostic trouble mode (normal or test) and
the output of the malfunction indicator lamp can be selected by
connecting the TE1, TE2 and E1 terminals on the data link con-
nector 2, as shown later.
A test mode function has been added to the functions of the self±
diagnosis system of the normal mode for the purpose of detecting
malfunctions such as poor contact, which are difficult to detect in
the normal mode. This function fills up the self±diagnosis system.
The test mode can be implemented by the technician following the
appropriate procedures of check terminal connection and opera-
tion described later. (See page EG±492) EG±490
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 1999 of 2543
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±598.
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±491).
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±492
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2002 of 2543
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).
Trouble Area
Malfunction
Indicator
Lamp*
1
Memory*2
See page
Trouble Area
Normal
Mode
Test
Mode
Memory
See page
±
±
±
±
±
Open or short in crankshaft position sensor, camshaft
position sensor No.1, No.2 circuit
Crankshaft position sensor
Camshaft position sensor No.1, No.2
Starter
ECM
ON
N.A.
EG±515
Open or short in crankshaft position sensor circuit
Crankshaft position sensor
ECM
ON
N.A.
Open or short in crankshaft position sensor circuit
Mechanical system malfunction (skipping teeth of
timing belt, belt stretched)
Crankshaft position sensor
ECM
N.A.
ON
EG±518
Mechanical system malfunction (skipping teeth of
timing belt, belt stretched)
Camshaft position sensor No.1, No.2
ECM
ON
N.A.
Open or short in IGF circuit from igniter to ECM
Igniter
ECM
ON
N.A.
EG±519
ECM
ON
N.A.
X
EG±524
*1, 2: See page EG±502.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±495
Page 2003 of 2543
DTC
No.
Number of
MIL BlinksCircuitDiagnostic Trouble Code Detecting Condition
(1) Open or short in heater circuit of main heated oxygen
sensor (Fr) for 0.5 sec. or more.
(2) Main heated oxygen sensor (Fr) signal voltage is reduced to
between 0.35 V and 0.70 V for 90 sec. under conditions
Main Heated
Oxygen Sensor
Signal(a) ~ (d):
(2 trip dectection logic)*3
(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 0.45 V
Open or short in engine coolant temp. sensor circuit for 0.5
sec. or more
Open or short in intake air temp. sensor circuit for 0.5 sec.
or more
(1) Main heated oxygen sensor voltage is 0.45 V or less (lean)
for 90 sec. under conditions (a) and (b):
(2 trip dectection logic)*3
(a) Engine speed: 1,500 rpm or more
(b) Engine coolant temp.: 70°C or more
(a) Engine speed: Below 950 rpm
(b) Engine coolant temp.: 80°C (176°F) or more
(2 trip dectection logic)*4
(2) Engine speed varies by more than 20 rpm over the preced±
ing crank angle period during a period of 20 sec. or more
under conditions (a) and (b):
Intake Air
Temp. Sensor
Signal
Engine Coolant
Temp. Sensor
Circuit
Air±Fuel
Ratio Lean
Malfunction
*3: See page EG±503. EG±496
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2004 of 2543
Trouble Area
Malfunction
Indicator
Lamp*
1
Memory*2
See page
Trouble Area
Normal
Mode
Test
Mode
Memory
See page
Open or short in heater circuit of main heated oxygen
sensor
Main heated oxygen sensor heater
ECM
ON
N.A.
Main heated oxygen sensor circuit
Mi h td
ON
ON
EG±525
Main heated oxygen sensor
ON
ON
Main heated oxygen sensor
Open or short in engine coolant temp. sensor circuit
Engine coolant temp. sensor
ECM
ON
ON
EG±530
Open or short in intake air temp. sensor circuit
Intake air temp. sensor
ECM
ON
ON
EG±532
Open or short in Main heated oxygen sensor circuit
Oen or short in Main heated oxygen sensor circuit
Main heated oxygen sensor
Main heated oxygen sensor
Ignition system
gy
ECM
Open or short in injector circuit
Oen or short in injector circuit
Fuel linepressure (injector leak blockage) ON ON EG 534
Fuel line pressure (injector leak, blockage)
Mechanical system malfunction (skipping teeth ofONONEG±534 Mechanical system malfunction (skipping teeth of
timing belt)
timing belt)
Ignition system
Ignition system
Compression pressure (foreign object caught in valve)
Compression pressure (foreign object caught in valve)
M i fl t (i itk)
Mass air flow meter (air intake)
ECM
ECM
*1, 2: See page EG±502
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±497
Page 2005 of 2543
DTC
No.
Number of
MIL BlinksCircuitDiagnostic Trouble Code Detecting Condition
(a) Engine speed: Below 950 rpm
(b) Engine coolant temp.: 80°C (176°F) or more
(2 trip dectection logic)*3
Engine speed varies by more than 20 rpm over the preceding
crank angle period during a period of 25 sec. or more
under conditions (a) and (b):
(1) Open or short in heater circuit of sub heated oxygen sensor
for 0.5 sec. or more
(2) Main heated oxygen sensor signal is 0.45 V or more and
sub heated oxygen sensor signal is 0.45 V or less under
conditions (a) ~ (c):
(2 trip dectection logic)*3
(a) Engine coolant temp.: 80°C (176°F) or more
(b) Engine speed: 1,5000 rpm or more
(c) Accel. pedal: Fully depressed for 2 sec. or more
Open or short in mass air flow meter circuit for 3 sec. or more
with engine speed less than 3,000 rpm
Open or short in turbo pressure sensor circuit for 0.5 sec. or
more
Open or short in BARO sensor circuit for 0.5 sec. or more
Sub Heated
Oxygen Sensor
Signal
Air±Fuel
Ratio Rich
Malfunction
Mass Air Flow
Meter Circuit
Turbo Pressure
Malfunction
Turbo Pressure
Sensor Circuit
Barometric
Pressure
Sensor Circuit
(c) Engine speed: 2,4000 rpm or more
(a) Mainfold absolute pressure: 200 kPa (2.0 kgf/cm2,
29 psi) or more
(b) Thottle valve opening angle: 20° or more
All conditions below are detected continuously for 2 sec. or more:
*3: See page EG±503. EG±498
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING
Page 2006 of 2543
Trouble Area
Malfunction
Indicator
Lamp*
1
Memory*2
See page
Trouble Area
Normal
Mode
Test
Mode
Memory
See page
Open or short in injector circuit
Fuel line pressure (injector leak, blockage)
Mechanical system malfunction (skipping teeth of
timing belt)
Ignition system
Compression pressure (foreign object caught in valve)
Mass air flow meter (air intake)
ECM
ON
ON
EG±534
Open or short in heater circuit of sub heated oxygen
sensor.
Sub heated oxygen sensor
ECM
ON
N.A.
Open or short in sub heated oxygen sensor circuit
Sub heated oxygen sensor
ECM
ON
ON
EG±540
Open or short in mass air flow meter circuit
Mass air flow meter
ECM
ON
N.A.
EG±544
Actuator (for waste gate valve)
Short in VSV for waste gate valve circuit
ECM
ON
N.A.
EG±546
Open or short in turbo pressure sensor circuit
Turbo pressure sensor
ECM
ON
ON
EG±549
ECM
ON
ON
EG±549
*1, 2: See page EG±502.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±499
Page 2007 of 2543
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