(See page IN±30).
(See page IN±30).
(See page IN±30).
(See page EG±294).
Check for open and short in harness and connector between terminal IDL2
of TRAC ECU and main throttle position sensor with TRAC ECU, ECM and
main throttle position sensor connectors disconnected (See page IN±30).
Check voltage of terminal VTA2 of ECM (See page EG±554).
Repair or replace harness or connector.
Check for short in harness between terminal IDL2 of TRAC ECU and body
ground with only main throttle position sensor connector connected (See
page IN±30).
Check and replace main throttle position sensor.
Check and replace ECM.
Check and replace TRAC ECU.
Check for short in harness between terminal IDL2 of TRAC ECU and body
ground with only ECM connector connected (See page IN±30).
Check for open and short in harness and connector between terminal
VTA2 of ECM and main throttle position sensor (See page IN±30).
Check main throttle position sensor (See page EG±555).
Check and replace ECM.
Repair or replace harness or connector.
Adjust or replace main throttle position sensor
See page EG±294).
Check and replace ECM.
BR±154± BRAKE SYSTEMTRACTION CONTROL SYSTEM (TRAC)
TORQUE SPECIFICATIONS
Part tightened NVm KgfVcm ftVlbf
Master cylinder X Piston stopper bolts
10
100
7
Master cylinder X Reservoir 1.7 17.5 15.2 in.Vlbf
Master cylinder X Brake booster 13 130 9
Brake line union nut M10
15
155
11
Brake line union nut M12 20 200 15
Brake booster clevis lock nut
25
260
19
Brake booster X Pedal bracket 13 130 9
Bleeder plug 11 11 0 8
Front disc brake caliper X Steering knuckle 2JZ±GTE
11 8
1,200
87
Front disc brake torque plate X Steering knuckle 2JZ±GE 11 8 1,200 87
Front disc brake caliper installation bolt 2JZ±GE 34 350 25
Front disc brake caliper X Flexible hose union bolt
30
310
22
Rear disc brake caliper X Axle carrier 2JZ±GTE 104 1,065 77
Rear disc brake torque plate X Axle carrier 2JZ±GE
104
1,065
77
Rear disc brake caliper installation bolt 2JZ±GE 34 350 25
Rear disc brake caliper X Flexible hose union bolt 30 310 22
ABS actuator X Actuator bracket
5.4
55
48 in.Vlbf
ABS actuator X 2±way 8.8 90 78 in.Vlbf
ABS actuator bracket X Body 19 195 14
Cruise control actuator X Body
19
195
14
Cruise control actuator X ABS actuator X Body 19 195 14
Front speed sensor installation bolt
7.8
80
69 in.Vlbf
Rear speed sensor installation bolt 7.8 80 69 in.Vlbf
TRAC actuator bracket X TRAC pump bracket or body 13 130 9
TRAC pump bracket X Body
19
195
14
TRAC pump bracket X Damper 7.8 80 69 in.Vlbf
TRAC pump bracket X TRAC pump bracket No.2 7.8 80 69 in.Vlbf
TRAC pump X TRAC pump bracket No.2
7.8
80
69 in.Vlbf
TRAC pump or damper X Union bolt 46 465 34
± BRAKE SYSTEMSERVICE SPECIFICATIONSBR±167
[2] SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the TOYOTA SUPRA fulfills various functions. The first function is the Diagnostic
Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU memory
at the time of occurrence, to be output by the technician during troubleshooting. Another function is the Input
Signal Check which checks if the signals from various switches are sent to the ECU correctly. The air condition-
ing system has an Actuator Check function whereby the ECU automatically operates the actuators of the damp-
er and blowermotor, etc. to check the operation. By using these check functions, the problem areas can be nar-
rowed down quickly and troubleshooting can be performed effectively. Diagnostic functions are incorporated
in the following systems in the TOYOTA SUPRA.
System
Diagnostic Trouble
Code Check
Input Signal Check
(Sensor Check)
Other Diagnosis
Function
Engine
Automatic Transmission
Anti±Lock Brake
Traction Control (Option)
Supplemental Restraint System
Cruise Control
Air Conditioning
O (with Test Mode)
O (with Test Mode)
O
O
O
O
O
O
O
O
O
O
O
Actuator Check
In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diagnos-
tic trouble code is still occurring or occurred in the past but returned to normal at present. In addition, it must
be checked in the problem symptom check whether the malfunction indicated by the diagnostic trouble code
is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes should be
checked before and after the symptom confirmation to determine the current conditions, as shown in the table
below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting for normally oper-
ating systems, thus making it more difficult to locate the problem, or in repairs not pertinent to the problem.
Therefore, always follow the procedure in correct order and perform the diagnostic trouble code check.
DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)
Confirmation of
symptoms
Diagnostic Trouble
Code Check
Problem Condition
Diagnostic
Trouble Code
Display
Problem symptoms
exist
Same Diagnostic
trouble code is dis-
played
Problem is still occurring in the diagnos-
tic circuit
%
Normal code is dis-
played
The problem is still occurring in a place
other than in the diagnostic circuit. (The
diagnostic trouble code displayed first is
either for a past problem or it is a sec-
ondary problem.)
%
No problem
symptoms exist
The problem occurred in the diagnostic
circuit in the past.
Normal Code Display
%
Problem symptoms
exist
Normal code is dis-
played
The problem is still occurring in a place
other than in the diagnostic circuit.
%
No problem
symptoms exist
Normal code is dis-
played
The problem occurred in a place other
than in the diagnostic circuit in the past.
IN±22± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
Troubleshooting
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
(a) Check (main heated) oxygen sensors operation.
(See oxygen sensor(s) inspection in SFI System)
(b) See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.
CO HC Phenomenon Causes
Normal
High
Rough idle
1. Faulty ignitions:
Incorrect timing
Fouled, shorted or improperly gapped plugs
Open or crossed high±tension cords (2JZ±GE)
Cracked distributor cap (2JZ±GE)
2. Incorrect valve clearance
3. Leaky EGR valve
4. Leaky intake and exhaust valves
5. Leaky cylinder
Low
High
Rough idle
(Fluctuating HC reading)
1. Vacuum leaks:
PCV hose
EGR valve
Intake manifold
Air intake chamber
Throttle body
IAC valve
Brake booster line
2. Lean mixture causing misfire
High
High
Rough idle
(Black smoke from exhaust)
1. Restricted air filter
2. Faulty SFI systems:
Faulty fuel pressure regulator
Clogged fuel return line
Defective ECT switch
Defective turbo pressure sensor (2JZ±GTE)
Faulty ECM
Faulty injector
Faulty throttle position sensor
Faulty VAF meter (2JZ±GE)
Faulty MAF meter (2JZ±GTE)
EG±8± ENGINEENGINE MECHANICAL
CYLINDER HEAD REMOVAL (2JZ±GE)
1. REMOVE ENGINE UNDER COVER
2. DRAIN ENGINE COOLANT
3. REMOVE AIR CLEANER DUCT
4. REMOVE AIR CLEANER, VAF METER AND INTAKE AIR
CONNECTOR PIPE ASSEMBLY
(See step 6 in engine removal in Engine Mechanical)
5. REMOVE DRIVE BELT
Loosen the drive belt tension by turning the drive belt tension-
er clockwise, and remove the drive belt.
6. REMOVE NO.2 FRONT EXHAUST PIPE
(See step 22 in engine removal in Engine Mechanical)
7. REMOVE EXHAUST MANIFOLDS
(a) Except California:
Remove the 4 nuts and manifold heat insulator.
(b) Disconnect the 2 (main heated) oxygen sensor connectors.
(c) Remove the 4 nuts, exhaust manifold and gasket.
Remove the No.1 and No.2 exhaust manifolds.
8. DISCONNECT PS PUMP WITHOUT
DISCONNECTING HOSES
(a) Disconnect these hoses:
(1) Air hose from No.4 timing belt cover
(2) Air hose from air intake chamber
(b) Remove the 2 bolts, and disconnect the pump housing from
the pump bracket.
HINT: Put aside the pump housing, and suspend it.
(c) Remove the 2 bolts and pump rear stay.
9. DISCONNECT BRAKE BOOSTER VACUUM HOSE
10. DISCONNECT EVAP HOSE
11. REMOVE THROTTLE BODY AND INTAKE AIR
CONNECTOR ASSEMBLY
(See injector removal in SFI System)
± ENGINEENGINE MECHANICALEG±41
19. INSTALL WATER BYPASS OUTLET AND NO.1 WATER
BYPASS PIPE
(See step 3 in water pump installation in Cooling System)
20. INSTALL TIMING BELT
(See steps 11 to 17 in timing belt removal)
21. INSTALL SPARK PLUGS
22. INSTALL DISTRIBUTOR AND CORDS ASSEMBLY
(See steps 2, 3 and 5 in distributor installation in Ignition
System)
23. CONNECT HIGH±TENSION CORDS TO CYLINDER HEAD
COVERS
(See step 1 in high±tension cords and cord clamps
installation in Ignition System)
24. INSTALL NO.3 TIMING BELT COVER
25. INSTALL CYLINDER HEAD REAR COVER
26. INSTALL NO.2 VACUUM PIPE AND VSV ASSEMBLY
27. INSTALL AIR INTAKE CHAMBER STAYS
HINT: The No.1 stay is marked with ºFº, and No.2 stay is
marked with ºRº.
(a) Install the No.1 stay with the bolt and nut.
Torque: 18 NVm (185 kgfVcm, 13 ftVlbf)
(a) Install the No.2 stay with the bolt and nut.
Torque: 18 NVm (185 kgfVcm, 13 ftVlbf)
28. I N S TA L L T H R OTTLE BODY AND INTAKE AIR
CONNECTOR ASSEMBLY
(See in injector removal in SFI System)
29. CONNECT EVAP HOSE
30. CONNECT BRAKE BOOSTER VACUUM HOSE
31. INSTALL PS PUMP
(a) Install the pump rear stay with the 2 bolts.
Torque: 39 NVm (400 kgfVcm, 29 ftVlbf)
(b) Install the pump housing with the 2 bolts.
Torque: 58 NVm (590 kgfVcm, 43 ftVlbf)
(c) Connect these hoses:
wAir hose to No.4 timing belt cover
wAir hose to air intake chamber
32. INSTALL EXHAUST MANIFOLDS
(a) Install a new gasket and the exhaust manifold with 4 new
nuts. Install the No.1 and No.2 exhaust manifolds.
Torque: 39 NVm (400 kgfVcm, 29 ftVlbf)
(b) Connect the 2 (main heated) oxygen sensor connectors.
(c) Except California:
Install the manifold heat insulator with the 4 nuts. EG±68
± ENGINEENGINE MECHANICAL
Sub heated
oxygen sensor
(California
only)
Heater coil resistance at 20°C (68°F)
11±16
Fuel cut rpm
Fuel return rpm
1,400 rpm
TORQUE SPECIFICATIONS
Part tightened NVm kgfVcm ftVlbf
Fuel line for union bolt
for flare nut
29
30
300
310
22
22
Fuel pressure regulator x Delivery pipe 8.8 90 78 in.Vlbf
Delivery pipe x Intake manifold 21 210 15
Actuator for ACIS x Air intake chamber 6.8 70 61 in.Vlbf
Fuel inlet pipe x Delivery pipe 41 420 30 Fuel return pipe x Fuel pressure regulator 27 280 20 Air intake chamber stay x Cylinder head 18 185 13
Air intake chamber stay x Air intake chamber
18
185
13
Intake air connector x Air intake chamber
27
270
20
Throttle body bracket x Throttle body
21
210
15
Throttle body bracket x Cylinder head 21 210 15
No.2 vacuum pipe x Intake manifold 27 270 20
EGR pipe x Cylinder head 27 270 20
EGR pipe x EGR valve 64 650 47
Fuel pressure pulsation damper x Fuel pipe support
for SST
41
35
420
350
30
25
Starter x Transmission 39 400 29
Fuel tank band x Body 39 400 29 VAF meter x Air cleaner case 10 100 7 Throttle body x Intake air connector 21 210 15
Vacuum tank x Intake manifold
21
210
15
Brake booster union x Air intake chamber
29
300
22
Air intake chamber x Intake manifold
27
270
20
EGR gas temperature sensor x EGR valve 20 200 14
Knock sensor x Cylinder block 44 450 33
Oxygen sensor (Except California) x Exhaust manifold 20 200 14
Main heated oxygen sensor (California) x Exhaust manifold 44 450 33
Sub heated oxygen sensor (California only) x Center exhaust pipe 20 200 14
± ENGINESFI SYSTEM (2JZ±GE)EG±257
(c) Disconnect these hoses:
(1) Air hose from IAC valve
Disconnect the IAC valve pipe from the clamp on the cyl-
inder head cover, and disconnect the air hose from the
IAC valve.
(2) Air hose (from air intake chamber) from vacuum pipe on
IAC valve pipe
(3) Air hose for EGR from valve pipe
(4) PCV hose from PCV valve
(5) Vacuum sensing hose from fuel pressure regulator
(6) Water bypass hose (from IAC valve) from No.4 water by-
pass pipe
(7) EVAP hose (from air intake chamber) from vacuum pipe
on manifold stay
(8) EVAP hose (from vacuum pipe on No.4 water bypass
pipe) from No.2 vacuum pipe
(9) EVAP hose (from charcoal canister) from No.2 vacuum
pipe
(10) PS air hose from air intake chamber
(11) Brake booster vacuum hose from union on air intake
chamber
8. DISCONNECT EGR GAS TEMPERATURE SENSOR
CONNECTOR
(a) Disconnect the connector from the No.2 vacuum pipe.
(b) Disconnect the sensor connector from the wiring connector.
9. REMOVE EGR PIPE
(a) Remove the union bolt holding the EGR pipe to the EGR
valve.
Torque: 64 NVm (650 kgfVcm, 47 ftVlbf)
(b) Remove the 2 bolts, EGR pipe and gasket.
INSTALLATION HINT: Use a new gasket.
Torque: 27 NVm (270 kgfVcm, 20 ftVlbf)
10. REMOVE NO.4 WATER BYPASS PIPE
Remove the 2 bolts and water bypass pipe.
11. REMOVE MANIFOLD STAY
Remove the 2 bolts and manifold stay.
Torque: 39 NVm (400 kgfVcm, 29 ftVlbf)
EG±276± ENGINESFI SYSTEM (2JZ±GTE)