1986 TOYOTA SUPRA light

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

Diagnosis Inspection (Normal Mode)
MALFUNCTION INDICATOR LAMP CHECK
1. The Malfunction Indicator Lamp will come on when the
ignition switch is turned ON and the engine is not running.
HINT: If the malfunction indicator lamp does not light up, pro-
ceed to troubleshooting of the telltale light RH (See page
BE±48).
2. When the engine is started, the malfunction indicator lamp
should go off.
If the light remains on, the diagnosis system has detected a
malfunction or abnormality in the system.
DIAGNOSTIC TROUBLE CODE CHECK
1. Turn ignition switch ON.
2. Using SST, connect terminals between TE1 and E1 of data
link connector 1 or 2.
SST 09843±18020
3. Read the diagnostic trouble code from malfunction indicator
lamp.
HINT: If a diagnostic trouble code is not output, check the TE1
terminal circuit (See page EG±598).
As an example, the blinking patterns for codes; normal, 12
and 31 are as shown on the illustration.
4. Check the details of the malfunction using the diagnostic
trouble code table on page EG±494.
5. After completing the check, disconnect terminals TE1 and
E1, and turn off the display.
HINT: In the event of 2 or more malfunction codes, indication
will begin from the smaller numbered code and continue in
order to the larger.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±491

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

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

 
 
 Trouble Area
 
 
 
Malfunction
Indicator
Lamp*
1
 
 
 Memory*2
 
 
 See page
 
 
Trouble Area
 
 
Normal
Mode 
 
Test
Mode 
 
Memory
 
 
See page
 
 
 

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
 
 
 
ON
 
 
 
ON
 
 
 

 
 
 
EG±552
 
 
 
 
 
 
 
 
 

No.1 vehicle speed sensor

Telltale light RH

Open or short in No.1 vehicle speed sensor circuit

ECM
 
 
 
 
 
 
 
 
 
OFF
 
 
 
 
 
 
 
 
 
OFF
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
EG±556
 
 
 

Open or short in starter signal circuit

Open or short in ignition switch or starter relay circuit

ECM
 
 
 
N.A
 
 
 
OFF
 
 
 
X
 
 
 
EG±559
 
 
 

Open or short sub±throttle position sensor circuit

Sub±throttle position sensor

ECM
 
 
 
OFF
 
 
 
ON
 
 
 

 
 
 
EG±552
 
 
 

Open or short in No.1 knock sensor circuit

No.1 Knock sensor (loosensess)

ECM
 
 
 
ON
 
 
 
N.A
 
 
 

 
 
 
EG±561
 
 
 

ECM
 
 
 
ON
 
 
 
N.A
 
 
 
X
 
 
 
EG±561
 
 
 

Open or short in No.2 knock sensor circuit

No.2 Knock sensor (looseness)

ECM
 
 
 
ON
 
 
 
N.A
 
 
 

 
 
 
EG±561
*1,
2: See page EG±502.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±501

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

Malfunction detection (1st time)
(temporarily recorded)Malfunction detection (2nd time)
(MIL lights up)
 
 
 Trouble Area
 
 
 
Malfunction
Indicator
Lamp*
1
 
 
 Memory*2
 
 
 See page
 
 
Trouble Area
 
 
Normal
Mode 
 
Test
Mode 
 
Memory
 
 
See page
 
 
 
 
 
 

Open in EGR gas temp. sensor circuit

Short in VSV circuit for EGR

EGR hose disconnected, valve stuck

Clogged EGR gas passage

ECM
 
 
 
 
 
 
ON
 
 
 
 
 
 
ON
 
 
 
 
 
 

 
 
 
 
 
 
EG±564
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Open or short in fuel pump ECU circuit

Fuel pump ECU

Fuel pump

ECM power source circuit

ECM
 
 
 
 
 
 
 
 
 
 
 
 
 
 
OFF
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ON
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
EG±568
 
 
 
 
 
 

A/C switch circuit

Throttle position sensor IDL circuit

Park/neutral position switch circuit

Accelerator pedal and cable

ECM
 
 
 
 
 
 
N.A.
 
 
 
 
 
 
OFF
 
 
 
 
 
 
X
 
 
 
 
 
 
EG±571
*3: This indicates items for which º2 trip detection logicº is used. With this logic, when a logic malfunction is
first detected, the malfunction is temporarily stored in the ECM memory. If the same case is detected again
during the second drive test, this second detection causes the Malfunction Indicator Lamp to light up.
The 2 trip repeats the same mode a 2nd time. (However, the IG switch must be turned OFF between the
1st trip and 2nd trip).
In the Test Mode, the Malfunction Indicator Lamp lights up the 1st trip a malfunction is detected.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±503

FAIL±SAFE CHART
If any of the following codes is detected, the ECM enters fail±safe mode.
 DTC No. Fail±Safe Operation Fail±Safe Deactivation Conditions
 
 14
 
 Fuel cut
 
 6 IGF signals detected in 6 consecutive
ignitions
 16 Torque control prohibited Returned to normal condition 
 22
 
 THW is fixed at 80°C (176°F)
 
 Returned to normal condition
 24 THA is fixed at 20°C (68°F) Returned to normal condition
 
 
 
 
 
 
31
 
 
 
 
 
 
Volume of air flowing is measured by turbo pressure
Sensor to determine injection volume and ignition
Timing
 
 
 
 
 
 
Returned to normal condition
 
 34
 
 Fuel cut
 
 Returned to normal condition
  Turbo  
  
Turbo
Pressure Fuel cut Returned to normal condition
 35 Sensor  
 
 
35
 
 
BARO
Sensor 
 
Atmospheric pressure is fixed at
101.3 kPa (760 mmHg, 29.92 inVHg) 
 Returned to normal condition
 
 
 
 
41
 
 
 
 
VTA1 is fixed at closed throttle position
 
 
 
 
The following must each be repeated at
least 2 times consecutively:

0.1 V
VTA1
0.95 V

IDL: ON
 
 
 
47
 
 
 
VTA2 is fixed at wide open throttle
Position 
 
 
The following must be repeated at least 2
times consecutively

0.1 V
VTA2
0.95 V
 52 Max. timing retardation IG switch OFF
 53 Max. timing retardation Returned to normal condition
 55 Max. timing retardation IG switch OFF
Back±Up Function
If there is trouble with the program in the ECM and the ignition signals (IGT) are not output from the microcomput-
er, the ECM controls fuel injection and ignition timing at predetermined levels as a back±up function to make
it possible to continue to operate the vehicle.
Furthermore, the injection duration is calculated from the starting signal (STA) and the throttle position signal
(IDL). Also, the ignition timing is fixed at the initial ignition timing, 10
°BTDC, without relation to the engine speed.
HINT: If the engine is controlled by the back±up function, the malfunction indicator lamp lights up to warn the
driver of the malfunction but the diagnostic trouble code is not output. EG±504
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING