1986 TOYOTA SUPRA fuse

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

DIAGNOSTIC TROUBLE CODE CHECK
USING TOYOTA HAND±HELD TESTER
1. Hook up the TOYOTA hand±held tester to the DLC2.
2. Read the diagnostic trouble codes by following the prompts
on the tester screen.
Please refer to the TOYOTA hand±held tester operation's manual
for further details.
DIAGNOSTIC TROUBLE CODE
CLEARANCE
1. After repair of the trouble areas, the diagnostic trouble code
retained in the ECM memory must be cleared out by
removing the EFI No.1 fuse (30A) from R/B No.2 for 10
seconds or more, with the ignition switch OFF.
HINT:
wCancellation can also be done by removing the negative
(±) terminal cable from the battery, but in this case, other
memory systems (clock, etc.) will also be cancelled out.
wIf it is necessary to work on engine components
requiring removal of the negative (±) terminal cable from
the battery, a check must first be made to see if a
diagnostic trouble code has been recorded.
2. After cancellation, road test the vehicle to check that a normal
code is now read on the malfunction indicator lamp.
If the same diagnostic trouble code appears, it indicates that
the trouble area has not been repaired thoroughly.
ECM DATA MONITOR USING TOYOTA
HAND±HELD TESTER
1. Hook up the TOYOTA hand±held tester to the DLC2.
2. Monitor the ECM data by following the prompts on the tester
screen.
HINT: TOYOTA hand±held tester has a ºSnapshotº function which
records the monitored data.
Please refer to TOYOTA hand±held tester operator's manual for
further details.
ECM TERMINAL VALUES
MEASUREMENT USING TOYOTA
BREAK±OUT±BOX AND TOYOTA
HAND±HELD TESTER
1. Hook up the TOYOTA break±out±box and TOYOTA
handheld tester to the vehicle.
2. Read the ECM input/output values by following the prompts
on the tester screen.
HINT: TOYOTA hand±held tester has a ºSnapshotº function. This
records the measured values and is effective in the diagnosis of
intermittent problems.
Please refer to TOYOTA hand±held tester/TOYOTA break±out±
box operator's manual for further details.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±493

CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSTIC TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diagnostic trouble
code is no longer detected.
Malfunction: Main Heated Oxygen Sensor Deterioration
It is vital that this test routine is adhered to detect the malfunction:
(1) Disconnect the EFI No.1 fuse (30 A) for 10 sec. or more, with IG switch OFF. Initiate test
mode (Connect terminal TE2 and E1 of data link connector 2 with IG switch OFF).
(2) Start the engine and warm up with all ACC switch OFF.
(3) Idle the engine for 3 min.
(4) Accelerate gradually within the range 1,300 ~ 1,7700 rpm (centered around 1,500 rpm) with
the A/C switch ON and D position for A/T (5th for M/T).
HINT:
Ensure engine rpm does NOT fall below 1200 rpm.

Gradually depress the accelerator pedal at a suitable rate to comply with the test re±
quirements on the above graph.

Never allow engine rpm to drop at any time during the test.
(5) Maintain the vehicle speed at 64 Ð 80 km/h (40 Ð 50 mph).
(6) Keep the vehicle running for Ð 2 min. after starting acceleration.
HINT: If a malfunction exists, the Malfunction Indicator Lamp will light up after approx. 60 sec.
from the start of acceleration.
NOTICE: If the conditions in this test are not strictly followed, detection of the malfunc±
tion will not be possible. EG±526
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

HINT: Before this test, check the feedback voltage for oxygen sensor.
(1) Disconnect the EFI No.1 fuse (30A) for 10 sec. or more, with IG switch OFF. Initiate test mode
(Connect terminal TE2 and E1 of data link connector 2 with IG switch OFF).
(2) Start the engine and warm up.
(3) Idle the engine for 3 min.
(4) Race the engine quickly to 4,000 rpm 3 times using the accelerator pedal.
(5) Race the engine at 2,000 rpm for 90 sec.
HINT: If a malfunction exists, the malfunction indicator lamp will light up during step (4).
NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction
will not be possible.
Malfunction: Open or Short in Main Heated Oxygen Sensor
CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSTIC TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diagnostic
trouble code is no longer detected.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±535

CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSTIC TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diagnostic trouble
code is no longer detected.
(1) Disconnect the EFI No.1 fuse (30A) for 10 sec. or more, with IG switch OFF.
Initiate test mode (Connect terminal TE2 and E1 of data link connector 2 with
IG switch OFF).
(2) Start the engine and warm up with all ACC switched OFF.
(3) Idle the engine for 5 min.
(After the entine is started, do not depress the accelertor pedal.)
HINT: If a malfunction exists, the malfunction indicator lamp will light up during the 5 min.
idling period.
NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction
will not be possible.
Malfunction: Open or Short in Injector circuit, Injector Leak or Blockage
WIRING DIAGRAM
See page EG±527 for the WIRING DIAGRAM EG±536
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSTIC TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that
diagnostic trouble code is no longer detected.
(1) Disconnect the EFI No.1 fuse (30A) for 10 sec. or more, with IG switch OFF.
Initiate test mode (Connect terminal TE2 and E1 of data link connector 2 with
IG switch OFF).
(2) Start the engine and warm up with all ACC switched OFF.
(3) Drive the vehicle at 80 ~ 88 km/h (50 ~ 55 mph) for 10 min. or more.
(4) Stop at a safe place and idle the engine for 2 min. or less.
(5) Accelerate to 96 km/h (60 mph) with the throttle valve fully open.
HINT: If a malfunction exists, the malfunction indicator lamp will light up during step (5).
NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction
will not be possible.
Malfunction: Open or Short in Sub Heated Oxygen Sensor
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±541

Malfunction: Open in EGR Gas Temp. Sensor Circuit
(1) Disconnect the EFI No.1 fuse (30A) for 10 sec. or more, with IG switch OFF.
Initiate test mode (Connect terminal TE2 and E1 of data link connector 2 with IG
switch OFF).
(2) Start the engine and warm up.
(3) Idle the engine for 3 min.
(4) With the A/C ON and transmission in 5th position (A/T in 3rd speed) drive at 88 96
km/h (55 60 mph) for 4 min or less.
HINT: If a malfunction exists, the malfunction indicator lamp will light up during step (4).
NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction
will not be possible.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±565

Check for short in the harness and all the compo-
nents connected to IGN fuse (See Electrical Wir-
ing Diagram).
Remove IGN fuse from J/B No.1.
Check continuity of IGN fuse.
Continuity
Check IGN fuse.
Check ignition switch.
(1) Remove finish lower panel and finish lower
panel LH.
(2) Remove heater to register duct No.2.
Check continuity between terminals.
Check and repair harness and connector between
battery and ignition switch, ignition switch and en-
gine control module.
Replace ignition switch.
Terminal
Switch position
LOCK
ACC
ON
START
continuity
EG±578± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING