Toyota TOYOTA COMPUTER-CONTROLLED SYSTEM Installation guide

training manual
VOLUME 1 STEP 3 /
TCCS
(TOYOTA COMPUTER-
CONTROLLED SYSTEM)

FOREWOR D
This Training Manual has been prepared
for the use of technicians employed by Toyota's overseas
distributors and dealers
. This manual, "TCCS (Toyota Computer-Controlled System)", is Volume 1 of
the thirteen Training Manuals which constitute Step 3 of the program of skills which all Toyota New
TEAM*
technicians should master . It should also be used by the instructor in conjunction
with the
accompanying Instruction Guide .
The titles
of the New TEAM Step 3 Training Manuals are as follows
:
VOL .
TRAINING MANUALS VOL . TRAINING MANUAL S
1 TCCS (Toyota Computer-Controlled System) 8
NVH (Noise, Vibration & Harshness
)
2 Turbocharger & Supercharger 9
Fundamentals of Electronic s
3 Diesel Injection Pump 10 CCS
(Cruise Control System
)
4 ECT ( Electronically-Controlled Transmission)
1 1 Car Audio Syste m
5 Full-Time 4WD
12 Automatic Air Conditioning Syste m
6 TEMS & Air Suspension
13 SRS Airbag & Seat Belt Pretensione r
7
ABS & Traction Control Syste m
It is not enough just to "know" or "understand" - you need to master each task so that you can do
it
. For this reason, theory and practice have been combined in this Training Manual
. The top of each
page is marked either with a Q symbol to indicate that it is a Theory page or a® symbol to indicate
that it is a Practice page
.
Note that in regards to inspection and other procedures mentioned in the Practice section, this
Training Manual contains only the main points to be learned
; please refer to the relevant Repair
Manual(s) for details .
The following notations often occur in this manual, with the meanings as explained :
A potentially hazardous situation which could result in injury to people may occur i
f
CAUTION
instructions are not followed .
NOTICE
Damage to the vehicle or components may occur if instructions are not followed .
NOTE Notes or comments not included under the above two headings .
Information not required to pass the TEAM certification, but which may be useful t o
REFERENCE
instructors and to trainess who wish to gain a deeper knowledge of the subject .
*TEAM : TEAM stands for 'Technical Education for Automotive Maste
ry' , which is a training program divided into three steps
according to the technician's technical level
. This program makes it possible for technicians to receive the appropriate training for their
level in a systematic manner so as to help them achieve the skills and efficiency of skilled technicians in the sho
rt est possible time .

This Training Manual explains the TCCS
engine control system based on the 4A-FE engine . However,
representative engines other than the 4A-FE
engine have sometimes been selected to explain
mechanisms not found" on the 4A-FE engine
. In this way, explanations of as many mechanisms as
possible have been included .
All information contained in this manual is the most up-to-date at the time of publication
. However,
we reserve the right to make changes without prior notice .
TOYOTA MOTOR CORPORATIO
N
©1997 TOYOTA
MOTOR CORPORATION
All rights reserved . This book may not be repro-
duced or copied, in whole or in part, without the
written permission of Toyota Motor Corporation .

TABLE OF CONTENT
S
Page
ABBREVIATIONS AND ECU TERMINAL SYMBOL
S
ABBREVIATIONS . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 1
ECU TERMINAL SYMBOLS
. . . . . . . . . . . . . . . . . . . . . . 2
OUTLINE OF TCC S
WHAT IS TCCS? .. .. . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
HISTORY OF TCCS ENGINE CONTROL
SYSTEM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SYSTEM DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1
. Functions of engine control system . . . 8
2 . Construction of engine contro l
system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3
. Engine control system diagram
. . . . . . . . . 1 2
ELECTRONIC CONTROL SYSTE M
GENERAL . . . . . . . . . . . . . . . . . . . .. .
. . . . . . . . . . . . . . . . . . . . . . . . 13
POWER CIRCUITRY . . . . . . . . . . . .. .
. . . . . . . . . . . . . . . . . . 15
1 . Engine without stepper motor typ e
ISC valve . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 15
2 . Engine with stepper motor typ
e
ISC valve . .. . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
VC CIRCUITRY . . . . . . . . .. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . 16
GROUND CIRCUITRY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
MANIFOLD PRESSURE SENSO R
(VACUUM
SENSOR) . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
AIR FLOW METER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1 . Vane type .. .. . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2
. Optical Karman vortex type . . . . . . . . . . . . . . 21
3
. Hot-wire type . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 21-
1
THROTTLE POSITION SENSOR . . . . . . . . . . . . . . . . 22
1 . On-off type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2
. Linear type . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . 2 3
G AND NE SIGNAL GENERATORS . . . . . . . . . . .
. 24
1 . In-distributor type . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2 . Cam position sensor type . . . . . . . . ..
. . . . . . 27
3 . Separate type
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 2
8
WATER TEMPERATURE SENSOR . . . . . . . . . . . . . 30
INTAKE AIR TEMPERATURE SENSOR . . . .
. . . 30
OXYGEN SENSOR (02 SENSOR)
. . . . . . . . . . . 30- 1
1 . Zirconia element type
. . . . . . . . . . . . . . . . . . . 30-1
2 . Titania element type
. . . . . . . . . . . . . . . . . . . . . . . . .32
LEAN MIXTURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . 33
Page
VEHICLE SPEED
SENSOR . . . . . . . . . . . . . . . .
. . . . . . . . 3 4
1 . Reed switch type . . . . . . . . . . . . . . . . . . . .
. . . . . . . . 34
2 . Photocoupler type . . . . . . . . .
. . . . . . . . . . . . . . . . . 34
3
. Electromagnetic pickup type
. . . . . . . . . . . . 35
4 . MRE type . . . . . . . . . . . . . . . . . .. .. .
. . . . . . . . . . . . . . . . 3 6
STA SIGNAL . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . 38
NSW SIGNAL . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . 38
A/C SIGNAL .... . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 39
ELECTRICAL LOAD SIGNAL
. . .. . . . . . . . . . . . . . . . . 39
FUEL CONTROL SWITCH O
R
CONNECTOR . . . . . . . .. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . 40
EGR GAS TEMPERATURE SENSOR
. . . . . . . . . . 40
VARIABLE RESISTOR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
KICK-DOWN SWITCH
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 42
WATER TEMPERATURE SWITCH
. . . . . . . . . . . .
. 42
CLUTCH SWITCH
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
KNOCK SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . 43
HAC SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . 44
VAPOR PRESSURE SENSOR . . . . . . . . . . . . . . . . . .
. . 44
TURBOCHARGING PRESSURE SENSOR
. . . . 44
STOP LAMP SWITCH . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 45
OIL PRESSURE SWITCH . . . . . . . . . . .
. . . . . . . . . . . . . . 45
COMMUNICATIONS SIGNALS
. . . . . . . . . . . . . . . . . 4 5
1 . Throttle opening angle signals
. . . . . . . . . . 45
2 . Throttle opening angle signals fo
r
TRC system . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . 45
3 . Cruise control syste
m
communications signal
. . . . . . . . . . . . . . . . . . . . 46
4. TRC system
communications signal . . 46
5 . ABS communications signal
. . . . . . . . . . . . . 46
6 . Intercooler system warning signal
. . . . . 46
7 . EHPS system
communication s
signal . . . . . . . . . . . . . . . . . .. . . . . . . . .
. . . . . . . . . . . . . . . . . 47
8 . Engine speed signal
. . . . . . . . . . . . . . . . . . . . . . . . 47
9 . Engine immobiliser syste
m
communications
signal . . . . . . . . . . . . . . . . . . . . 47
DIAGNOSTIC TERMINAL(S) . . . . . . . . . . . . . .• .••••• 4
8
EFI (ELECTRONIC FUEL INJECTION
)
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . 49
TYPES OF EFI . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . 52
1 . D-type EFI . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . 52

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Page
DIAGNOSTIC CODES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8
FAIL-SAFE FUNCTIO
N
FAIL-SAFE FUNCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5
BACK-UP FUNCTIO N
BACK-UP FUNCTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7
TROUBLESHOOTIN G
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 149
HOW TO CARRY OU T
TROUBLESHOOTING
. . . . . . . . . . . . . . . . . . . . . . . . . . 150
PRE-DIAGNOSTIC QUESTIONING
. . . . . . . . . . . . . 152
SYMPTOM CHART . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . 1 5 4
® CHECKING AND CLEARING DIAGNOSTIC
CODE S
"CHECK ENGINE" LAMP CHECK . . . . . . . . .. .
.
. 159
OUTPUT OF DIAGNOSTIC CODE S
1 . Normal mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . 15 9
2 . Test mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 161
CLEARING DIAGNOSTIC CODE . . . . . . . . . .
. . . . .
. 16
2
IS SYMPTOM SIMULATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . 163
® BASIC INSPECTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
INSPECTION AND ADJUSTMEN T
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. 171
IDLE SPEED AND IDLE MIXTURE . . . . . . . . . . ..
. 172
MANIFOLD PRESSURE SENSO
R
(VACUUM SENSOR) . . . . . . . . . . . . . . . . . . . . . . . . . .
. 175
THROTTLE POSITION SENSO
R
(LINEAR TYPE) AND THROTTL
E
BODY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . 177
DISTRIBUTOR (G AND NE SIGNALS)
. . . . . . . . 180
INTAKE AIR TEMPERATURE
SENSOR . . . . . . . 181
FEEDBACK CORRECTION . . . . . . . . . . . . . . . . . . .
. . . . 182
Models with oxygen senso r
(02 sensor)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Models with
lean mixture sensor . . . . . . . . . . . 183
VARIABLE RESISTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
ISC VALV E
(DUTY-CONTROL ACV TYPE) . . . . . . . . . . . . . . 186
Pag e
APPENDIX
ENGINE CONTROL SYSTE M
SPECFICATION CHART .. ... . . ..
.. ... . . . ... ... . 18 8
DELETED FOR NEW EDITIO N
. . . . . ... ... . . . ... .. . 118, 119, 125, 126, 141 to 144,
166 and 174

ABBREVIATIONS AND ECU TERMINAL SYMBOLS - Abbreviations
4
ABBREVIATIONS AND ECU TERMINAL SYMBOL S
ABBREVIATION S
ABS Anti-Lock Brake System
ABV Air Bypass Valv e
AC Alternating Current
A/C Air Conditione r
ACIS Acoustic Control Induction System
ACV Air Control Valv e
Al Air Injection
AS Air Suctio n
ASV Air Switching Valv e
A/T Automatic Transmission
BTDC Before Top Dead Center
CA Crankshaft Angl e
CALIF Californi a
CCS Cruise Control System
CO Carbon Monoxid e
DIS Direct Ignition System
DLI Distributorless Ignition
EC European Countrie s
ECT Electronically-Controlled Transmission
ECU Electronic Control Uni t
EFI Electronic Fuel Injection
EGR Exhaust Gas Recirculatio n
EHPS Electro-Hydraulic Power Steering
ESA Electronic Spark Advanc e
FED . Federal
GEN . General Countrie s
HAC High-Altitude Compensation
HC Hydrocarbo n
HIC Hybrid Integrated Circui t
IIA Integrated Ignition Assembly
ISC Idle Speed Contro l
LED Light Emitting Diode
LS Lean Mixture Senso r
MRE Magnetic
Resistance Element
M/T Manual
Transmissio n
NOx Oxides of Nitrogen
OC Oxidation Catalyst
OD Overdrive
02 Oxygen
PS Power Steering
SCV Swirl Control Valve
SST Special Service Tool
SW Switc h
TCCS Toyota Computer-Controlled System
TDC Top Dead Cente r
TDCL *1 Toyota Diagnostic Communication
Link or Total Diagnostic
Communication Lin k
TEMS Toyota Electronically-Modulated
Suspension
Tr Transisto r
TRC*2 Traction Contro l
T-VIS Toyota-Variable Induction System
TWC Three-Way Catalys t
U .S
. United State s
VSV Vacuum Switching Valve
w/ Wit h
w/o Withou t
4WD 4-Wheel-Driv e
In vehicles sold at Lexus dealers in the U .S . and
Canada, this is called the "Total Diagnostic
Communication Link" . In Toyotas sold in other
countries, and in Toyotas sold at Toyota dealers
in the U .S . and Canada, it is called the "Toyota
Diagnostic Communication Link" . In this
manual, it is called the "Toyota Diagnostic
Communication Link"
.
*2 In
the U .S . and Canada, this is abbreviated to
TRAC .
/-- iw 1
c
Abbreviations in accordance with SAE terms
are used for vehicles sold in the U
.S .A . and
Canada . Refer to the Repair Manual for dif-
ferences between SAE terms and Toyota
terms .
Example :
ECM Engine Control Module
(= Engine ECU
)
ECT Engine Coolant Temperature
(= THW)
1

ABBREVIATIONS AND ECU TERMINAL SYMBOLS - ECU Terminal Symbol s
ECU TERMINAL SYMBOL S
SYMBOL MEANING
ABS Anti-Lock Brake Syste m
ACC1 Acceleration Signal No . 1(from
Thro tt le Position Sensor)
ACC2 Acceleration Signal No . 2 (fro m
Throttle Position Sensor)
A/C Air Conditione r
ACMG Air Conditioner Magnetic Clutch
ACT Air Conditioner Cut-Of f
Al Air Injection
AS Air Suctio n
A/D Auto Drive (Cruise Control System)
+B Ba tt e r y
+B1 Ba tt e ry No . 1
BATT Ba tt e r y
BF Ba tt e ry Fail Safe
BRK Brake
DFG Defogge r
E01 Ea
rt
h No
. 01 (Ground)
E02 Ea rt h No . 02 (Ground)
E1 Ea
rt
h No . 1 (Ground)
E2 Ea
rt
h No
. 2 (Ground )
ECT Electronically-Controlled Transmission
ELS Electrical Load Signa l
EGR Exhaust Gas Recirculation
FC Fuel Pump Contro l
FP Fuel Pump Control Relay
FPU Fuel Pressure-U p
FS Fail-Safe Rela y
G Group (Crankshaft Angle Signal )
G1 Group No .
1 (Crankshaft
Angle Signal)
G2 Group No .
2 (Crankshaft
Angle Signal)
G- Group Minus (-
)
HAC High-Altitude Compensatio n
HT Heater (for Oxygen Sensor or Lean
Mixture Sensor )
IDL Idle Switch (in Throttle Position
Sensor )
IGDA Ignition Distribution Signal A
IGDB Ignition Distribution Signal B
IGF Ignition Failure (Confirmation) Signal
IGSW Ignition Switc h
IGT Ignition Timing Signal
SYMBOL MEANIN G
ISC1 Idle Speed Control Signal No . 1
ISC2 Idle Speed Control Signal No
. 2
ISC3 Idle Speed Control Signal No . 3
ISC4 Idle Speed Control Signal No . 4
KD Kick-Dow n
KNK Knock Sensor
KS Karman Signa l
L7 Throttle Valve Opening Signal No
. 1
L2 Throttle Valve Opening Signal No
. 2
L3 Throttle Valve Opening Signal No . 3
LP Lam p
LS Lean Mixture Sensor
LSW Lean Burn Switch
M-REL EFI Main Rela y
N/C Neutral Clutch Switc h
NE Number of Engine Revolutions
Signa l
NE- Number of Engine Revolutions
Signal Minus (- )
NEO Number of Engine Revolutions
Signal Outpu t
No .10 (for Injectors)
No .20 (for Injectors )
NSW Neutral Sta rt Switch
OX Oxygen Senso r
OX + Oxygen Sensor ~+
OIL Oil Pressur e
OD Overdrive
PS Power Steerin g
PSW Power Switch (in Throttle Position
Sensor )
PIM Pressure, Intake Manifol d
R-P Regular or Premium Gasoline Signal
RSC Rota ry Solenoid Valve Close d
RSO Rota
ry
Solenoid Valve Open
SCV Swirl Control Valv
e
SPD Vehicle Spee d
SP2 Vehicle Speed No . 2
SP2- Vehicle Speed No . 2 Minus (-)
STA Sta rt e r
STJ Cold Sta rt Injecto r
2

ABBREVIATIONS AND ECU TERMINAL SYMBOLS
- ECU Terminal Symbol
s
SYMBOL MEANING
STP Stop Lamp Switch
T Test Termina l
TE1 Test Terminal, Engine No . 1
TE2 Test Terminal, Engine No . 2
THA Thermo, Intake Ai r
THG Thermo, Exhaust Gas
THW Thermo, Wate r
TR Traction Contro l
T-VIS Toyota-Variable Induction System
TSW Water Temperature Switc
h
VAF Voltage, Air-Fuel Ratio Control
VB Voltage, Batter y
VC Voltage, Constant
VF Voltage, Feedbac k
VG Voltage, Gram Intake Air
V-ISC VSV Type Idle Speed Control
VS Voltage, Slide Signa
l
VSH Voltage, Sub-Throttle Angle
VTA Voltage, Throttle Angle
VTH Voltage, Throttle Angl e
W "CHECK ENGINE" Warning Lamp
WIN Warning Lamp, Intercooler
F4$
3

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