1986 TOYOTA SUPRA lights
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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 40 of 878
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
Page 41 of 878
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
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Page 42 of 878
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
Page 140 of 878
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±388) the Engine Control Module (ECM) detects system mal-
functions relating to the sensors or actuators.
In the normal mode, the self±diagnosis system monitors 18
(California specification vehicles) or 17 (except for California and
Canadian specification) items, indicated by code No. as shown in
EG±388. A malfunction indicator 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, 12 (California specification vehicles) or 11 (ex-
cept for California and Canadian specification vehicles) items, in-
dicated by code No. as shown in EG±388 are monitored. If a mal-
function is detected in any one of the systems indicated by code
Nos. 13, 21, 22, 24, 25, 26, 27, 28, 35, 41, 71 and 78 (California
specification vehicles) or 13, 21, 22, 24, 25, 28, 35, 41, 71 and 78
(except for California and Canadian specification vehicles) 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±386).
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). This 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±386) EG±384
± ENGINE2JZ±GE ENGINE TROUBLESHOOTING
Page 153 of 878
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±453
Open or short in fuel pump ECU circuit
Fuel pump ECU
Fuel pump
ECM power source circuit
ECM
OFF
ON
EG±457
A/C switch circuit
Throttle position sensor IDL circuit
Park/neutral position switch circuit
Accelerator pedal and cable
ECM
N.A.
OFF
X
EG±460
*4: 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±GE ENGINE TROUBLESHOOTINGEG±397
Page 154 of 878
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 1 IGF detected in 3 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
Ignition timing fixed at 10°BTDC
Injection time fixed:
(Starting....9 msec.
(IDL ON....3.6 msec.
(IDL OFF....6.7 msec.
KS input 15 times/sec. or more
35
Atmospheric pressure is fixed at 101.3 kPa
(760 mmHg, 29.92 in.Hg)
Returned to normal condition
41
VTA1 is fixed at 0°
The following must each be repeated at least 2
Times consecutively:
0.25 V VTA 0.95 V
IDL: ON
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±398
± ENGINE2JZ±GE ENGINE TROUBLESHOOTING
Page 155 of 878
DTCCircuit
G, NE signal circuit (No.2)
Engine coolant temp. sensor
circuit
Intake air temp. sensor circuit
Throttle position sensor
circuit
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) 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) are output during the diagnostic trouble
code check, and inspection of the appropriate circuits reveals 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±387.
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 indi-
cates that the place where the wire harness, connector or ter-
minals being pulled or vibrated has a 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 thor-
oughly for faulty contacts, etc., then try the check again. If the
malfunction indicator lamp still does not go off, check and re-
place ECM.
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±399