1997 TOYOTA SUPRA lock

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit.
Normal code is
displayedThe 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
secondary problem.)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past.
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit.
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past.
IN-20- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
20 Author
: Date
:
1997 SUPRA (RM502U)
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.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the TOYOTA SU-
PRA.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Other Diagnosis
Function
Engine
Automatic Transmission
Anti-Lock Brake System
ABS & Traction Control System
Supplemental Restraint System
Cruise Control
Air Conditioning (with Check
Mode)
 (with Check
Mode)









Diagnostic Test
Mode
Diagnostic Test
Mode
Actuator Check
In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic 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 operating 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.

V08423 Knock Sensor 1
GRECM
KNK
E1 12
E6
WIRING DIAGRAM
DTC P0325Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
Knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelectric element which
generates a voltage when it becomes deformed, 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 Condition Trouble Area
P0325No knock sensor 1 signal to ECM with engine speed,
1,200 rpm or more.
Open or short in knock sensor1 circuit

Knock sensor 1 (looseness)

ECM
If the ECM detects the above diagnosis conditions, it operates the fall safe function in which the corrective retard angle
value is set to the maximum value.

Diagnostic Trouble Code No. and Detection Item

Circuit Description
The major role and operation, etc. of the circuit
and its component parts are explained.

Indicates the diagnostic trouble code, diagnostic
trouble code set parameter and suspect area of
the problem.

Wiring Diagram
This shows a wring diagram of the circuit.
Use the diagram together with ELECTRICAL
WIRING DIAGRAM to thoroughly understand the
circuit.
Wiring colors are indicated by an alphabetical code.
B = Black, L = Blue, R = Red, BR = Brown,
LG = Light Green, V = Violet, G = Green,
O = Orange, W = White, GR = Gray, P = Pink,
Y = Yellow
The first letter indicates the basic wire color and
the second letter indicates the color of the stripe. IN-26
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26 Author
: Date
:
1997 SUPRA (RM502U)
6. CIRCUIT INSPECTION
How to read and use each page is shown below.

V08425
LOCK
KNK
E6 Connector
(a) Remove the glove compartment.
(b) Disconnect the E6 connector of ECM.
INSPECTION PROCEDURE
Replace knock sensor. 1 Check continuity between terminal KNK of ECM connector and body ground.
OK:
Check knock sensor (See page SF-67).Measure resistance between terminal KNK of ECM connector
and body ground.
Resistance: 1 MW or higher
Connector being checked is connected.
Indicates the condition of the connector of ECU during the check.
PREPARATION:
CHECK:
2Go to step 3.
OK OK
NG

Indicates the position of the ignition switch during the check.
Check from the connector back side.
(with harness)
Ignition Switch LOCK (OFF)
Ignition Switch START
LOCKIgnition Switch ON
Ignition Switch ACC
STARTON
ACC

Indicates the place to check the voltage or resistance.

Indicates the connector position to checked, from the front or back side.
Connector being checked is disconnected. Check from the connector front side. (without harness)
In this case, care must be taken not to bend the terminals.
E6 Connector KNKWire Harness
E6 Connector KNK
A00255 AB0117
A00265

Inspection Procedure
Use the inspection procedure to determine
if the circuit is normal or abnormal, and, if
it is abnormal, use it to determine whether
the problem is located in the sensors,
actuators, wire harness or ECU.
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-27
27 Author
: Date
:
1997 SUPRA (RM502U)

B01402
Sensor Side
ECU Side
IN0378
Sensor SideECU Side
IN0380
Sensor SideECU Side
IN0381
Pull Lightly
Looseness of Crimping
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-29
29 Author
: Date
:
1997 SUPRA (RM502U)
2. CONTINUITY CHECK (OPEN CIRCUIT CHECK)
(a) Disconnect the connectors at both ECU and sensor
sides.
(b) Measure the resistance between the applicable terminals
of the connectors.
Resistance: 1 W or less
HINT:

Measure the resistance while lightly shaking the wire har-
ness vertically and horizontally.

When tester probes are inserted into a connector, insert
the probes from the back. For waterproof connectors in
which the probes cannot be inserted from the back, be
careful not to bend the terminals when inserting the tester
probes.
3. RESISTANCE CHECK (SHORT CIRCUIT CHECK)
(a) Disconnect the connectors at both ends.
(b) Measure the resistance between the applicable terminals
of the connectors and body ground. Be sure to carry out
this check on the connectors on both ends.
Resistance: 1 MW or higher
HINT:
Measure the resistance while lightly shaking the wire harness
vertically and horizontally.
4. VISUAL CHECK AND CONTACT PRESSURE CHECK
(a) Disconnect the connectors at both ends.
(b) Check for rust or foreign material, etc. in the terminals of
the connectors.
(c) Check crimped portions for looseness or damage and
check if the terminals are secured in lock portion.
HINT:
The terminals should not come out when pulled lightly.
(d) Prepare a test male terminal and insert it in the female ter-
minal, then pull it out.
NOTICE:
When testing a gold-plated female terminal, always use a
gold-plated male terminal.
HINT:
When the test terminal is pulled out more easily than others,
there may be poor contact in that section.

IN04I-01
- INTRODUCTIONTERMS
IN-33
33 Author
: Date
:
1997 SUPRA (RM502U)
TERMS
ABBREVIATIONS USED IN THIS MANUAL
AbbreviationsMeaning
ABSAnti-Lock Brake System
ALRAutomatic Locking Retractor
APPROX.Approximately
A/T, ATMAutomatic Transmission
AT FAutomatic Transmission Fluid
BTDCBefore Top Dead Center
CBCircuit Breaker
CDCompact Disc
CRSChild Restraint System
DOHCDouble Over Head Cam
DPDash Pot
ECUElectronic Control Unit
ELREmergency Locking Retractor
ESAElectronic Spark Advance
EXExhaust (Manifold, Valve)
FIPGFormed in Place Gasket
FLFusible Link
FrFront
H-FuseHigh Current Fuse
IGIgnition
INIntake (Manifold, Valve)
J/BJunction Block
LEDLight Emitting Diode
LHLeft-Hand
LLCLong Life Coolant (Year Around Coolant)
LSDLimited Slip Differential
Max.Maximum
Min.Minimum
MPMultipurpose
M/TManual Transmission
O/D, ODOverdrive
O/SOversize
P&BVProportioning and Bypass Valve
PCVPositive Crankcase Ventilation
PPSProgressive Power Steering
PSPower Steering
RHRight-Hand
RrRear
SRSSupplemental Restraint System
SSMSpecial Service Materials
SSTSpecial Service Tools
STDStandard

28SUPRAÐNEW FEATURES
2) Cornering
Supposing that the differential case is not moving, rotating the left side gear counterclockwise, causes planet gear
A (which meshes with the left side gear) to rotate clockwise.
Furthermore, planet gear B, which is paired with planet gear A, rotates counterclockwise, causing the right side gear
(which meshes with planet gear B) to rotate clockwise.
Therefore the left and right side gears rotate in the opposite direction each other, thus accomplishing a motion
differential.
3) Limited Slip Differential Operation
Limited slip is accomplished primarily b the friction that is generated between the planet gear's tooth tips and the
differential case's inner wall, and the friction that is generated between the side gear end face and the thrust washer.
The principle of limited slip enables the resultant reaction force F1 (which is created by the meshing reaction of the
planet gear and the side gear and the meshing reaction of the planet gears themselves) to push the planet gear in the
direction of the differential case in proportion to the input torque.
Due to the reaction force F1, the friction force u F2 (which is generated between the side gear end face and the thrust
washer) applies a force to cancel out the rotational difference between the side gears themselves as well as between
the side gear and the differential case.

30SUPRAÐNEW FEATURES
2. ABS
General
The ABS (Anti±Lock Brake System) is designed to control the brake fluid pressure of the brake wheel cylinder to
help prevent wheel lock±up in instances of panic braking, and thus maintaining vehicle directional stability and
control.
System Diagram

34SUPRAÐNEW FEATURES
c. Operation
The hydraulic system of the ABS has 3 or 4 circuits. Although the hydraulic circuit described below has 1 circuit,
it is applicable to other circuits as well.
i) During Normal Braking (ABS not Activated)
During normal braking, the ABS is not activated and
the ECU dose not send control signal.
When the brake pedal is depressed, the fluid passes
from port A to port B, and then flows to the brake
wheel cylinder.
When the brake pedal is released, brake fluid returns
from the brake wheel cylinder to the master cylinder
through port B to port A and No. 1 Check Valve.

Condition of Actuator
Part Name
Signal from
ABS ECUOperation
Pressure
Holding ValveOFFPort AOpen
Pressure
Reduction
Valve
OFFPort BClosed
Pump MotorOFFRotating

Hydraulic Circuit
ii) During Emergency Braking (ABS Activated)
 Pressure Reduction Mode
When the wheel about to lock , the control signal from
the ECU causes port A to close and port D to open,
thus engaging the pressure reduction mode.
At this time the brake fluid flows from the wheel
cylinder, through ports C and D, to the reservoir
reducing the wheel pressure.
At the same time the brake fluid is pumped and
returned to the master cylinder.

Condition of Actuator
Part Name
Signal from
ABS ECUOperation
Pressure
Holding ValveONPort AClosed
Pressure
Reduction
Valve
ONPort DOpen
Pump MotorONRotating

Hydraulic Circuit