fuel ISUZU TROOPER 1995 Repair Manual

ENGINE FUEL 6C -11
MAIN DATA AND SPECIFICATIONS
TORQUE SPECIFICATIONS
Fig. 6C-15
20 (14)-M8
29
(22)-M14
N·m (lb·ft)

604-4 IGNITION SYSTEM
Fig. 604A-5
~ INSPECTION AND REPAIR
The spark plug affects entire engine performance and
therefore its inspection is very important.
• Check electrode and insulator for presence of
crack, and replace if any.
• Check electrode for wear, and replace if neces­
sary.
• Check gasket for damage, and replace if neces­
sary.
• Measure insulation resistance with an ohmmeter,
and replace if faulty.
• Adjust spark plug gap to 1.0(0.04) -1.1 (0.043)
mm(in).
• Check fuel and electrical systems if spark plug is
extremely dirty.
• Use spark plugs having low heat value (hot type
plug) if fuel and electrical systems are normal.
• Use spark plugs having high heat value (cold type
plug) if insulator and electrode are extremely
burned.
Sooty spark plugs
Much deposit of carbon or oil on the electrode and
insulator of spark plug reduces the engine perfor­
mance.
Possible causes:
• Too rich mixture
• Retarded ignition timing
• Presence of oil in combustion chamber
• Incorrectly adjusted spark plug gap
Burning electrodes
This fault is characterized by scorched or heavily
oxidized electrode or blistered insulator nose.
Possible causes:
• Too lean mixture
• Advanced ignition timing
• Improper heat value
Measuring Insulation Resistance
• Measure insulation resistance using a 500 volt
megaohm meter. (Fig. 604-6)
Fig.
604-6
• Replace spark plugs if measured value is out of
standard.
I @!.j Insulation resistance MQ 50 or more
Cleaning Spark Plugs
• Clean spark plugs with a spark plug cleaner.
• Raise the ground electrode to an angle of 45 to 60
degrees. If electrode is wet, dry it before cleaning.
• After spark plug is thoroughly cleaned, check
insulator for presence of crack.
• Clean threads and metal body with a wire brush.
• File the electrode tip if electrode is extremely
worn.
• Bend the ground electrode to adjust the spark
plug gap. (Fig. 604-7)
Fig. 604-7
•

6E2-2 DRIVEABILITY AND EMISSIONS
DRIVEABILITV AND EMISSIONS GENERAL INFORMATION
CONTENTS
General Information
Driveability ....................... .
Emissions
........................ .
Maintenance
Schedule .............. .
Introduction ...................... .
Electronic Engine
Control .......... .
What This Section Contains ........ .
Blocking Drive Wheels
Visual/Physical
Underhood Inspection
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
Basic
Knowledge required . . . . . . . . . . . . 6E2-4
Basic Electric Circuits . . . . . . . . . . . . . .
6E2-4
Use
of Circuit Testing Tools . . . . . . . . . 6E2-4
Use
of Digital Volt-Ohm Meter (DVOM). 6E2-4
Diagnostic
Information . . . . . . . . . . . . . . . 6E2-4
"Check Engine" Malfunction Indicator
Lamp (MIL) . . . . . . . . . . . . . . . . . . . . 6E2-4
Intermittent "Check Engine"
Malfunction Indicator Lamp (MIL) . . 6E2-4
Reading Diagnostic
Trouble Codes . . . 6E2-5
Clearing
Trouble Codes . . . . . . . . . . . . 6E2-5
Diagnostic Test
Mode .............. 6E2-5
Engine Control
Module Learning
Ability . . . . . . . . . . . . . . . . . . . . . . . . 6E2-6
Field
Service Mode . . . . . . . . . . . . . . . . 6E2-6
Standard Nomenclature
for Certain
Electrical/Electronic
Components
and Systems . . . . . . . . . . . . . . . . . . . 6E2-6
Abbreviations and Glossary of Terms ..... 6E2-11
Driveability and Emissions
Section Summary ................... 6E2-12
Section .,. A"
Diagnostic Procedure Summary ...... 6E2-13
Data Link Connector
"SCAN Tools" ..... 6E2-14
Data
List (FO) ...................... 6E2-14
"SCAN Tool" Limitations and Use ...... 6E2-14
Intermittent Conditions ............ 6E2-14
"SCAN Tool" Positions ............... 6E2-14
Injector Pulse Width ............... 6E2-14
Closed Loop/Open Loop . . . . . . . . . . . .
6E2-14
Trouble Codes ................... 6E2-14
Throttle Position (TP) Sensor . . . . . . . . 6E2-14
Throttle Angle . . . . . . . . . . . . . . . . . . . 6E2-15 Heated
Oxygen
Sensor (H02S)
Vehicle Speed Sensor (VSS) ....... .
Programmable Read Only Memory ID .
Revolution
Per Minute (RPM) ...... .
Mile Per Hour (MPH) ............. .
Engine
Coolant Temperature (ECT) .. .
Intake Air Temperature (IAT)
Sensor
...................... .
Manifold Absolute Pressure (MAP) .. .
Barometric Pressure (BARO) ....... .
Exhaust Gas Recirculation
(EGR)
(ON/OFF) .................... .
Short Term (S.T.) Fuel Trim and
Long Term
(LT.) Fuel Trim ...... .
Long Term
(LT.) Fuel Trim ........ .
Idle Air Control (lAC) Counts ....... .
Desired Revolution
Per Minute ..... .
Air Conditioning (A/C) Request ..... .
Air Conditioning (A/C) Clutch ...... .
Power Steering Pressure (PSP)
Switch ...................... .
Battery Positive Voltage .......... .
Spark Advance .................. .
Start Up Engine Coolant .......... .
Engine
Speed (RPM) ............. .
Fuel Trim Enable ................ .
Air/Fuel Ratio .................. .
Induction Air Control ............. .
Section B -Driveability Symptoms ... .
Section C -Component Systems .... .
Engine
Control Module (ECM)
and
Sensors .................. .
Fuel Control System ............. .
Electric
Fuel Pump (in-tank) ....... .
Evaporative Emission
(EVAP)
Control System ................ .
Ignition Control (IC) .............. .
Exhaust Gas Recirculator
(EGR) .... .
Air Conditioning (A/C) Clutch Control .
Positive Crankcase Ventilation (PCV) .
Tools Needed
to Service the System .... .
General Specifications
............... .
Vacuum Hose Routing Diagram
........ .
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-18
6E2-21
6E2-22
~
... ...
•

---
DRIVEABILITV AND EMISSIONS 6E2-3
ALL NEW ISUZU VEHICLES ARE CERTIFIED BY THE UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY AS CONFORMING TO THE REQUIREMENTS OF THE REGULATIONS FOR THE CONTROL OF AIR
POLLUTION FROM NEW MOTOR VEHICLES. THIS CERTIFICATION IS CONTINGENT ON CERTAIN
ADJUSTMENTS BEING SET TO FACTORY STANDARDS. IN MOST CASES, THESE ADJUSTMENT POINTS
EITHER HAVE BEEN PERMANENTLY SEALED AND/OR MADE INACCESSIBLE TO PREVENT INDISCRIMINATE
OR ROUTINE ADJUSTMENT IN THE FIELD. FOR THIS REASON, THE FACTORY PROCEDURE FOR
TEMPORARILY REMOVING PLUGS, CAPS, ETC., FOR PURPOSES OF SERVICING THE PRODUCT, MUST BE
STRICTLY FOLLOWED AND, WHEREVER PRACTICABLE, RETURNED TO THE ORIGINAL INTENT OF THE
DESIGN.
GENERAL INFORMATION
DRIVEABILITY
The driveability diagnosis procedures apply to various
systems in current
ISUZU vehicles. The procedures
assume
that the vehicle is worked on properly at one
time and the
problem is due to time, wear, dirt or other
causes.
Start with the introduction that follows. This
will describe a systematic diagnostic procedure.
Any system disconnected during diagnosis should be
reconnected. This
includes wires, hoses, linkage, etc.
EMISSIONS
The exhaust emission control systems used on
ISUZU engines perform a specific function to lower
exhaust emissions while maintaining good fuel
economy and driveability.
MAINTENANCE SCHEDULE
Refer to the Maintenance Schedule in Section "OB"
General Information for the maintenance service that
should be performed to retain emission control
performance.
INTRODUCTION
ELECTRONIC ENGINE CONTROL
All engines have an Engine Control Module (ECM)
to control the fuel system. The ECM varies the air/
fuel ratio by controlling the fuel flow through the
injectors.
In addition, the ECM controls the ignition timing,
fuel pump, and various other systems.
It is important to review the component sections
and
wiring diagrams in this Section for specific
components
controlled by the ECM and what
systems are non-ECM controlled.
WHAT THIS SECTION CONTAINS
Each ISUZU engine has system controls to reduce
exhaust emissions
while maintaining good
driveability and fuel economy. •
This Section explains:
•
How to use the Driveability and Emission
Section
"6E2" engines.
• A brief description of systems used to
control fuel and emissions.
• Abbreviations that are used in Driveability
and Emissions.
• Special tools used to diagnosis and repair a
system.
Before checking the
system, adhere to the
following information:
BLOCKING DRIVE WHEELS
The vehicle drive wheels should always be
blocked, and parking brake firmly set, while
checking the system.
VISUAL/PHYSICAL UNDERHOOD
INSPECTION
A careful visual and physical underhood
inspection must
be performed as part of any
diagnostic procedure
or in finding the cause of an
emissions test failure. This can often lead to fixing
a
problem without further steps. Inspect all
vacuum hoses for correct routing, pinches, cuts,
or disconnections. Be sure to inspect hoses that
are
difficult to see beneath the throttle body and
common chamber.
Inspect all the wires in the
engine
compartment for correct and good
connections, burned or chaffed spots, pinched
wires, or contact with sharp edges or hot exhaust
manifolds. This visual/physical inspection is very
important. It must be done carefully and
thoroughly.

......, .., LU
READING DIAGNOSTIC TROUBLE CODES
(Fig. 6E2-1)
The provision for communicating with the Engine
Control Module (ECM) is the Data Link Connector
(DLC) (See Fig. 6E2-1 ). The DLC is located behind
the
lower front instrument panel. It is used in the
assembly plant
to receive information in checking
that the engine is operating properly before it
leaves the plant. The diagnostic trouble code(s)
(DTCs) stored in the ECM's memory can be read
either through a hand-held diagnostic scannner
plugged into the
DLC or by counting the number
of flashes of the "Check Engine" Malfunction
Indicator Lamp (MIL) when the diagnostic test
terminal
ofthe DLC is grounded. The DLC terminal
"1" (diagnostic request) is pulled "Low"
(grounded) by jumpering to DLC terminal "3",
which is a ground wire. This will signal the ECM
that you want to "flash" DTC(s), if any are present.
Once terminals "1" and "3" have been connected,
the ignition switch
must be moved to the "ON"
position, with the engine not running. At this
point, the
"Check Engine" MIL should flash DTC 12
three times consecutively. This
would be the
following flash, sequence: "flash, pause, flash­
flash,
long pause, flash, pause, flash-flash, long
pause, flash, pause, flash-flash". DTC 12 indicates
that the ECM's diagnostic system is operating.
If
DTC 12 is not indicated, a problem is present
within the diagnostic system itself, and should be
addressed
by consulting the appropriate
diagnostic chart in
DRIVEABILITY AND
EMISSIONS (SECTION 6E2-A).
Following the output of DTC 12, the "Check
Engine" MIL
will indicate a DTC three times if a
DTC is present, or it will simply continue to output
DTC 12. If more than one DTC has been stored in
the
ECM's memory, the DTC(s) will be outputfrom
the lowest to the highest, with each DTC being
displayed three times.
--
Eig tU!2-1-...
DRIVEABILITY AND EMISSIONS 6E2-5
CLEARING TROUBLE CODES
When the ECM sets a trouble code, the "Check
Engine" MIL
will come "ON" and a trouble code
will be stored in memory. If the problem is
intermittent, the light
will go out after 10 seconds,
when the fault goes away. However, the trouble
code
will stay in the ECM memory until the battery
positive voltage
to the ECM is removed.
Removing battery positive voltage
for 30 seconds
will clear all stored trouble codes.
Trouble
Codes should be cleared after repairs
have been completed. Also, some Diagnostic
Charts will tell you to clear the DTC(s) before using
the chart. This
allows the ECM tosetthe DTCwhile
going through the chart, which will help to find the
cause
of the problem more quickly.
wcAUTION:
• To prevent ECM damage, the key must be "OFF"
when disconnecting or reconnecting power to
ECM (for example battery cable, ECM pigtail, ECM
fuse, jumper cables, etc.)
When using a hand-held diagnostic scanner,
or
"Scan tool" to read the DTC(s), clearing the DTC(s)
is done in the same manner as in the above
procedure.
DIAGNOSTIC TEST MODE
When the diagnostic test terminal is grounded
with the ignition "ON" and the engine "OFF", the
system
will enter what is called the Diagnostic
Test Mode.
In this diagnostic test mode the ECM
will:
1. Flash the "Check Engine" MIL "ON" and
"OFF" rapidly (indicating the system is
operating correctly).
2. Display any stored trouble codes by flashing
the
"Check Engine" MIL. Each DTC will be
flashed three times, then
DTC 12 will be
flashed again.
3. Energize all ECM controlled relays and
solenoids except
fuel pump relay. This
allows checking circuits which may be
difficult to energize without driving the
vehicle and being under particular operating
conditions.
4. The idle air control valve moves to its fully
extended position on most models, blocking
the
idle air passage. This is useful in checking
the
minimum idle speed.

6E2-6 DRIVEABILITY AND EMISSIONS
FIELD SERVICE MODE
ENGINE
CONTROL MODULE (ECM)
LEARNING ABILITY
The Engine Control Module (ECM) has a
"learning"
ability which allows it to make
corrections
for minor variations in the fuel system
to improve driveability. If the battery is
disconnected to clear diagnostic codes, or for
repair, the "learning" process has to begin all over
again. A change
may be noted in the vehicle's
performance. To "teach" the vehicle, make sure
the engine is at operating temperature, and drive
at part throttle, with moderate acceleration and
idle conditions, until normal performance returns.
lfthe diagnostic test terminal is grounded with the
engine running, the system is in
"Open" or
"Closed Loop".
In "Open Loop" the "Check Engine" malfunction
indicator lamp flashes
two and one-halftimes per
seconds.
In "Closed Loop", the light flashes once per
second.
Also, in "Closed
Loop", the light will stay "OFF"
most of the time if the system is too lean. It will
stay"ON" mostofthetime if the system is too rich.
While the system is in Field Service Mode, the
ECM will be in the following diagnostic test mode:
1. New trouble codes cannot be stored in the
ECM.
2. The closed loop timer is bypassed.
STANDARD NOMENCLATURE FOR /
CERTAIN ELECTRICAL/ELECTRONIC COMPONENTS AND SYSTEMS /
Starting with the 1993 model, lsuzu Motors will be complying with the Society of Automotive ~ngineers
(SAE) Recommended Practice J 1930. J 1930 is an industry wide standard that was ad6pted into
government regulations and requires certain electrical and electronic components and
syster;ns be known
by the same
nomenclature that have the same function. This standard is also being applied to
abbreviations and acronyms.
This standard is being used in
all 1993 service publications.
To make this standard work, some names and abbreviations are being replaced
with those recommended
by the
SAE Standard. What follows is a partial listing of former ISUZU names and abbreviations besides
the
new ISUZU names and abbreviations.
Former ISUZU Name New ISUZU Name Term
3Gr
Third Gear -3GR
3rd Gear
Third Gear -3GR
4Gr
Fourth Gear -4GR
4th Gear
Fourth Gear -4GR
A/C Air Conditioning -A/C
A/C
Relay Air Conditioning Relay -A/C Relay
Absolute Presure Sensor
Manifofd Absolute Pressure Sensor -MAP Sensor
AC Air Conditioning -A/C
AC Generator . Generator -GEN
ACC Air Conditioning -A/C
Accel
Accelerator Pedal -AP
Accelerator
Accelerator Pedal -AP
ACG Generator -GEN
Air Cleaner Element(s) / Air Cleaner Filter -ACL Filter
Air Cleaner Filter Ele;nent Air Cleaner Filter -ACL Filter
Air Conditioning / Air Conditioning -A/C
Air Injection Reaction System Secondary Air Injection System -AIR System
ALDL Data Link Connector -
DLC
ALDL Diagnostic Connector DLC Diagnostic Connector -DLC Diagnostic Connector ,.
, ....

6E2-8 DRIVEABILITY AND EMISSIONS
Former ISUZU Name New ISUZU Name Term
Crankshaft Reference Signal Crankshaft Position -CKP
Crankshaft Sensor
Crankshaft Position Sensor -CKP Sensor
Crankshaft Speed
Engine Speed -
RPM
Crankshaft Speed Sensor
Engine Speed Sensor -RPM Sensor
CTS Engine Coolant Temperature Sensor -ECT Sensor
D.I.S Electronic Ignition -El
Detonation Sensor
Knock Sensor-KS
Diagnostic Circuit Check On-Board Diagnostic System Check -OBD System Check
Diagnostic Code Diagnostic Trouble Code -DTC
Diagnostic Mode
Diagnostic Test Mode-DTM
Diagnostic Terminal
Diagnostic Test Terminal -DTT
Digital Electronic
Fuel Injection Multipart Fuel Injection -MFI
Digital Fuel Injection Multipart Fuel Injection -MFI
Digital Fuel Injection Sequential Multipart Fuel Injection -SFI
Direct Ignition Systme Electronic Ignition System -El System
DIS Electronic Ignition -El
DIS Module
Ignition Control Module -ICM
DIS Reference Electronic Ignition Reference -El Reference
Distributor
HEI Module Distributor Ignition Control Module -Dl Control Module
Distributorless Ignition System Electronic Ignition System -
El System
ECM Engine Control Module -ECM
ECM Controlled Air Conditioning Air Conditioning Compressor Clutch Control System -A/C
Compressor Clutch Control System
ECU Transmission Control Module -TCM
EECS Evaporative Emission-EVAP
EEPROM Electrically Erasable Programmable Read Only Memory-
EEPROM
EFI Throttle Body Fuel Injection -TBI
EGR Exhaust Gas Recirculation -EGR
EGR B/P Transducer EGR Backpressure Transducer -EGR BPT
EGR Valve Exhaust Gas Recirculation Valve -EGR Valve
Electronic Control Module Engine Control Module -ECM
Electronic Control Unit Powertrain Control Module -PCM
Electronic Engine Control Module Engine Control Module -ECM
Electronic Fuel Injection Multipart Fuel Injection -MFI
Electronic Spark Control Circuit Knock Sensor Circuit -KS Circuit
Electronic Spark Control System Knock Sensor System -KS System
Electronic Spark Timing Ignition
Control -IC
Electronic Spark Timing Circuit Ignition Control Circuit -IC Circuit
Electronically Controlled Pulse
Air Pulsed Secondary Air Injection System -PAIR System
System
Engine
Calibration Unit Programmable Read Only Memory -PROM
•

DRIVEABILITY AND EMISSIONS 6E2-9
Former ISUZU Name New ISUZU Name Term
Engine Coolant Temperature
Engine Coolant Temperature -ECT
Engine Crank Signal Crankshaft Position -CKP
Engine RPM Engine Speed -RPM
ESC Knock Sensor System-KS System
ESC Module Knock Sensor Module -KS Module
EST Ignition Control -IC
Evaporative Emission Control Evaporative Emission Control System -EVAP Control System
Exhaust Oxygen Sensor
Oxygen Sensor -
02S
Fourth Gear
Fourth Gear -4GR
Fuel Pump Fuel Pump -FP
Fuel Pump Relay
Fuel Pump Relay -FP Relay
GND Ground-GND
GAD Ground-GND
Ground Ground-GND
HC Hydrocarbon -HC
Hg Hydrargyrum-Hg
High Energy Ignition Distributor Ignition -Dl
Hydrocarbons
Hydrocarbon -HC
lAC
Idle Air Control-lAC
lAC Valve
Idle
Air Control Valve-lAC Valve
IACV Idle
Air Control Valve -lAC Valve
Idle
Air Control Idle Air Control -lAC
Idle
Speed Control Idle Speed Control -ISC
Ignition Module
Ignition Control Module -ICM
Inter Cooler Charge Air Cooler -CAC
ISC Idle Speed Control -ISC
Knock Signal Knock Sensor Signal -KC Signal
Lean Exhaust
Lean Heated Oxygen Sensor Signal -Lean H02S Signal
Lean Exhaust
Lean Oxygen Sensor Signal -Lean 02S Signal
Lean Mixture Signal Lean Heated Oxygen Sensor Signal -Lean H02S Signal
Lean Mixture Signal Lean Oxygen Sensor Signal -Lean 02S Signal
M/C Mixture Control -MC
Manifold Air Temperature Intake Air Temperature-IAT
Manifold
Air Temperature Sensor Intake Air Temperature Sensor-IAT Sensor
Manifold Pressure Manifold Absolute Pressure -MAP
MAP
Manifold Absolute Pressure -MAP
MAP Sensor
Manifold Absolute Pressure Sensor -MAP Sensor
MAT Intake Air Temperature-IAT
MEM-CAL Programmable Read Only Memory -PROM
Mem-Cal Error Programmable Read Only Error -PROM Error
Mode Diagnostic
Test Mode -DTM

6E2-10 DRIVEABILITY AND EMISSIONS
Former ISUZU Name New ISUZU Name Term
MPFI Injector Multiport Fuel Injection Injector -MFI Injection
MPH Mile Par Hour -MPH
Multi-Port Injection
Multiport Fuel Injection -MFI
02 Oxygen-02
02 Sensor Oxygen Sensor -02S
OBD On-Board Diagnostic -OBD
Oxygen Sensor
Heated Oxygen Sensor -H02S
Oxygen
Sensor Exhaust Oxygen Sensor -02S
P/N
Park/Neutral Position -PNP
Park/Neutral
Park/Neutral Position -PNP
Park/Neutral Switch Park/Neutral Position Switch -PNP Switch
PFI Multiport Fuel Injection -MFI
Port Fuel Injection Multiport Fuel Injection -MFI
Pressure Regulator
Fuel Pressure Control Valve
PROM Programmable Read Only Memory -PROM
PSPS Power Steering Pressure Switch-PSP Switch
Pulse Air Pulsed Secondary Air Injection -PAIR
Pulse Air Injection System Pulsed Secondary Air Injection System -PAIR System
Pulse Air System Pulsed Secondary Air Injection System -PAIR System
Pulse Width Modulate Pulse Width Modulate -PWM
PWM Pulse
Width Modulate -PWM
Rich Exhaust
Rich Heated Oxygen Sensor Signal -Rich H02S Signal
Rich Exhaust
Rich Oxygen Sensor Signal -Rich 02S Signal
Rich Mixture Signal Rich Heated Oxygen Sensor Signal -Rich H02S Signal
Rich Mixture Signal Rich Oxygen Sensor Signal -Rich 02S Signal
RPM Revolution Per Minute -RPM
SCAN
Scan Tool -ST
Scan Data Scan Tool Data -ST Data
Secondary
Air System Secondary Air Injection System -AIR System
Secondary
Air Valves Secondary Air Injection System Valves -AIR System Valve
Secondary Throttle Plate
Induction Air Control Plate System -lAC Plate System
Secondary Throttle
Plate System Induction Air Control Plate System -lAC Plate System
System Too Lean
Lean Heated
Oxygen Sensor Signal -Lean H02S Signal
System Too Rich
Rich Heated Oxygen Sensor Signal -Rich H02S Signal
System Voltage Battery Positive Voltage -B+
TB Throttle Body -TB
TBI Throttle Body Fuel Injection -TBI
Temperature Gauge
Engine Coolant Temperature Gause -ECT Gauge
Thermal Vacuum Switch
Thermal Vacuum
Valve -TVV
Thermal Vacuum Valve Thermal Vacuum Valve -TVV
Thermostatic Air Cleaner Air Cleaner -ACL

DRIVEABILITY AND EMISSIONS 6E2-11
Former ISUZU Name New ISUZU Name Term
Throttle Position Switch Wide Open Throttle Switch -WOT Switch
Throttle Switch
Wide Open Throttle Switch -WOT Switch
Throttle Valve Throttle
Body -TB
TPS Throttle Position Sensor -TP Sensor
Transmission ECU Transmission Control Module -TCM
TWC Three
Way
Catalytic Converter -TWC
Vacuum Switching Valve Vacuum Switch Valve -VSV
Vehicle Speed Sensor Vehicle
Speed Sensor
-VSS
vss Vehicle Speed Sensor -VSS
vsv Vacuum Switch Valve -VSV
WOT
Wide Open Throttle -WOT
ABBREVIATIONS AND GLOSSARY OF TERMS
Abbreviations used in this section are listed below in
alphabetical order with an explanation of the
abbreviation. There are some variations in the use
of
periods and in capitalization (as mph, m.p.h., Mph, and
MPH) for abbreviations used in this Section, but all
types are acceptable.
A/T -AUTOMATIC TRANSMISSION
AVM-ANALOG VOLT METER
CKT -CIRCUIT
DOHC-DUAL OVERHEAD CAMSHAFTS
DTM-DIAGNOSTIC TEST MODE
A particular state of operation.
DVOM-DIGITAL VOLT OHM METER
ECT -ENGINE COOLANT TEMPERATURE
ECM-ENGINE CONTROL MODULE
A metal box (located in passenger compartment)
containing
electronic circuitry which electrically
controls
and monitors air/fuel and emission systems
on
computer command control, and turns "ON" the
"Check Engine"
Malfunction Indicator Lamp when a
malfunction occurs in the system.
EGR-EXHAUST GAS RECIRCULATION
Method of reducing NOx emission levels by causing
exhaust gas
to be added to air/fuel mixture in
combustion chamber, thus
cooling combustion.
FED-FEDERAL
Vehicle/Engine available in all states except California.
GROUND
The negative (-) side of the battery. Also could be a
wire (conductor) shorted to ground.
HC-HVDROCARBONS
One of the pollutants found in engine exhaust.
Hg-MERCURV
A calibration material used as a standard for vacuum
measurement.
HIGH IMPEDANCE VOLTMETER
Has high opposition to the flow of electrical current.
Good
for reading circuits with low currentflow, such as
found in electronic systems because it allows tests to
be made without affecting the circuit.
IAT -INTAKE AIR TEMPERATURE
Air temperature in the intake manifold.
IAT-INTAKE AIR TEMPERATURE SENSOR
Measures the underhood temperature.
IC-IGNITION CONTROL
ECM controlled spark timing
IDEAL MIXTURE
The air/fuel ratio which provides the best
performance,
while maintaining maximum conversion
of exhaust emissions. Typically it is 14.7:1.
IGN-IGNITION
INPUTS
Information from sources (such as Engine Coolant
Temperature Sensors, Oxygen Sensor, etc.) to the
ECM that indicate how the systems are performing.
INTERMITTENT
Occurs now and then; not continuously. In electrical
circuits, refers to occasional open, short, or ground.
liP-INSTRUMENT PANEL
ISC-IDLE SPEED CONTROL
ECM-controlled solenoid used to route vacuum to
control idle speed under various engine loads.
KM/H-KILOMETER PER HOUR
A metric unit measuring speed needed to travel
distance of one kilometer (1 000 meters) in one hour.