1997 TOYOTA SUPRA lock

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-201
429 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0171 System too Lean (Fuel Trim)
DTC P0172 System too Rich (Fuel Trim)
CIRCUIT DESCRIPTION
ºFuel trimº refers to the feedback compensation value compared against the basic injection time. Fuel trim
includes short-term fuel trim and long-term fuel trim.
ºShort-term fuel trimº is the short-term fuel compensation used to maintain the air-fuel ratio at its ideal
theoretical value. The signal from the heated oxygen sensor indicates whether the air-fuel ratio is RICH or
LEAN compared to the ideal theoretical value, triggering a reduction in fuel volume if the air-fuel ratio is rich,
and an increase in fuel volume if it is lean.
ºLong-term fuel trimº is overall fuel compensation carried out long-term to compensate for continual devi-
ation of the short-term fuel trim from the central value due to individual engine differences, wear over time
and changes in the usage environment.
If both the short-term fuel trim and long-term fuel trim are LEAN or RICH beyond a certain value, it is de-
tected as a malfunction and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When the air fuel ratio feedback is stable after engine warning
up, the fuel trim is considerably in error on the RICH side
(2 trip detection logic)

Air intake (hose loose)

Fuel line pressure

Injector blockage

Heated oxygen sensor malfunction

Mass air flow meter

Engine coolant temp. sensor
P0172
When the air fuel ratio feedback is stable after engine warning
up, the fuel trim is considerably in error on the LEAN side
(2 trip detection logic)

Fuel line pressure

Injector blockage, leak

Heated oxygen sensor malfunction

Mass air flow meter

Engine coolant temp. sensor
HINT:

When DTC P0171 is recorded, the actual air-fuel ratio is on the LEAN side. When DTC P0172 is re-
corded, the actual air-fuel ratio is on the RICH side.

If the vehicle runs out of fuel, the air-fuel ratio is LEAN and DTC P0171 is recorded. The MIL then
comes on.

If the total of the short-term fuel trim value and long-term fuel trim value is within ± 35 %, the system
is functioning normally.
INSPECTION PROCEDURE
1 Check air induction system (See page SF-1).
NG Repair or replace.
OK
DI4SY-01

P22425
Knock Sensor 1
(On front side)
1W
Knock Sensor 2
(On rear side)
1WB
B 50
49
KNK2 KNK1ECM
E1
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-209
437 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0325 Knock Sensor 1 Circuit Malfunction
DTC P0330 Knock Sensor 2 Circuit Malfunction
CIRCUIT DESCRIPTION
Knock sensors are fitted one each to the front and rear of the left side of the cylinder block to detect engine
knocking. This sensor contains a piezoelectric element which generates a voltage when it becomes de-
formed, which occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition
timing is retarded to suppress it.
DTC No.DTC Detecting ConditionTrouble Area
P0325No knock sensor 1 signal to ECM with engine speed between
2,050 rpm and 5,950 rpm
Open or short in knock sensor 1 circuit

Knock sensor 1 (looseness)

ECM
P0330No knock sensor 2 signal to ECM with engine speed between
2,050 rpm and 5,950 rpm
Open or short in knock sensor 2 circuit

Knock sensor 2 (looseness)

ECM
If the ECM detects the above diagnosis conditions, it operates the fail safe function in which the corrective
retard angle value is set to the maximum value.
WIRING DIAGRAM
DI4T0-01

S05422
To Turbo
Charcoal
Canister
Fuel Tank
ECMIntake Manifold VSV for
EVAP
S01079
Battery
EB
W-B
BB-W
R/B No.2
EFI No.1
EFI Main Relay
2 2A
2
2 2
2
35
1 2
B-R
B-YB-REA22VSV for EVAP
1274
B
ECM
EVAP
E01
B+
GR24
A
M-REL
V
EA18 1 DI-234
- DIAGNOSTICSENGINE (2JZ-GTE)
462 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0441 Evaporative Emission Control System
Incorrect Purge Flow
CIRCUIT DESCRIPTION
To reduce HC emissions, evaporated fuel from the fuel tank is routed through the charcoal canister to the
intake manifold for combustion in the cylinders.
The ECM changes the duty signal to the VSV for EVAP so that the intake quantity of HC emissions is ap-
propriate for the driving conditions (engine load, engine speed, etc.) after the engine is warme up.
DTC No.DTC Detecting ConditionTrouble Area
P0441
The proper response to the computer command does not oc-
cur
(2 trip detection logic)

Open or short in VSV circuit for EVAP

VSV for EVAP

Vacuum hose blocked or disconnected

ECM

Charcoal canister
WIRING DIAGRAM
DI4T6-01

A00727
LOCK
Check Harness A
ECM
A33
BATT(+)
N08419
EFI FuseR/B No.2
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-283
511 Author
: Date
:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check voltage between terminal BATT of ECM connector and body ground.
PREPARATION:
Connect Check Harness A (See page DI-164).
CHECK:
Measure voltage between terminal BATT of ECM connector
and body ground.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-28).
NG
2 Check EFI fuse.
PREPARATION:
Remove EFI fuse from R/B No.2.
CHECK:
Check continuity of EFI fuse.
OK:
Continuity
NG Check for short in all the harness and compo-
nents connected to EFI fuse.
OK
Check and repair harness or connector be-
tween battery, EFI fuse and ECM.

S05425
Battery 1
B
2A
AM232
MAIN
5
1
Starter Relay
2 2 2 2
W-R
4IB1
W-R
Ignition Switch 78
B-W
J/B No.1 64
ST
1J1KBB13
IJ2B-WB(for MT)
1
2Clutch
Start
Switch
B-W
2
IJ1
BBB B B
B
R/B No.2
L-O810 254
W-B
L-O
L-O
Theft Deterrent
and Door Lock
Control ECU
IH
IB3 IF2
T3T7
Starter 1
S3 B 3
EA1
EA2
1
B
5 6(for AT)
Park/
Neutral
Position
SwitchECM
STA
E1 77
B
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-301
529 Author
: Date
:
1997 SUPRA (RM502U)
Starter Signal Circuit
CIRCUIT DESCRIPTION
When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore
necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection
volume for the starting injection control and after-start injection control.
WIRING DIAGRAM
DI4TT-01

FI6897
Pressure
Regulator
From Fuel Tank To
Fuel
Tank
(Return) Intake
Manifold ECMVSV
S03472
Battery
B
EB
W-BEFI No.1
R/B
No.2
1
2A2
B-W
222
2
EFI Relay
R/B
No.2
21 5
3B-R5
EA2
B-Y
EA18
VSV for Fuel
Pressure Control B-R1
2W-L73
B
GR24
AECM
FPU
E01
B+
M-REL
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-309
537 Author
: Date
:
1997 SUPRA (RM502U)
Fuel Pressure Control Circuit
CIRCUIT DESCRIPTION
The ECM turns on a VSV (Vacuum Switching Valve) to draw the
air into the diaphragm chamber of the pressure regulator if it de-
tects that the temperature of the engine coolant is too high dur-
ing engine staring.
The air drawn into the chamber increases the fuel pressure to
prevent fuel vapor lock at high engine temperature in order to
help the engine start when it is warm.
Fuel pressure control ends approx. 120 sec. after the engine is
started.
WIRING DIAGRAM
DI4TV-01

DI4V4-01
Vehicle Brought to Workshop
Customer Problem Analysis
P. DI-441
Check and Clear DTC (Precheck)
P. DI-442Items inside
are titles of pages in this manual,
with the page number in the bottom portion. See
the pages for detailed explanations.
Problem Symptom ConfirmationSymptom Simulation
P. IN-18
Symptom
does not occur
Symptom
occurs
DTC Check
P. DI-442
Sensor CheckCircuit Inspection
P. DI-453 ~ DI-498
DTC Chart
P. DI-447 Malfunction codeProblem Symptoms Chart
P. DI-452
Check for Fluid Leakage
P. DI-498
Identification of Problem
Normal code
Repair
Confirmation Test
End
1
2
3
4
5
67
89
10
11
Step 2, 5, 8, 9, 11:Diagnostic steps permitting the use of the
TOYOTA hand-held tester or TOYOTA
break-out-box.
DI-440
- DIAGNOSTICSANTI-LOCK BRAKE SYSTEM
668 Author
: Date
:
1997 SUPRA (RM502U)
ANTI-LOCK BRAKE SYSTEM
HOW TO PROCEED WITH TROUBLESHOOTING
Troubleshooting in accordance with the procedure on the following pages.

DI4V5-01
ABS Check Sheet
Inspector 's
Name:
Customer 's Name
Date Vehicle
Brought InRegistration Year Registration No.
Frame No.
Odometer Reading/ /
/ /
Date Problem First Occurred
Frequency Problem Occurs/ /
ContinuousIntermittent ( times a day)
Remains ONDoes not Light Up
Symptomskm
miles
ABS does not operate.
ABS Warning Light
AbnormalABS does not operate efficiently.
Check ItemTRAC Indicator
LightNormalDoes not Light Up
2nd TimeNormal Code
Malfunction Code (Code )
Normal CodeMalfunction Code (Code )
1st Time
DTC Check
- DIAGNOSTICSANTI-LOCK BRAKE SYSTEM
DI-441
669 Author
: Date
:
1997 SUPRA (RM502U)
CUSTOMER PROBLEM ANALYSIS CHECK