1998 ISUZU TROOPER Ecm

6E±226
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
0018
Manifold Absolute Pressure (MAP) Sensor
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure. The MAP sensor
signal voltage to the ECM varies from below 2 volts at idle
(high vacuum) to above 4 volts.
The MAP sensor is used to determine the following:

Boost pressure for injector control.

Barometric pressure (BARO).
If the ECM detects a voltage that is lower than the
possible range of the MAP sensor, DTC P0107 will be set.
A signal voltage higher than the possible range of the
sensor will set DTC P0108. An intermittent low or high
voltage will set DTC P1107 or DTC P1106, respectively.
The ECM can detect a shifted MAP sensor. The ECM
compares the MAP sensor signal to a calculated MAP
based on throttle position and various engine load factors.
If the ECM detects a MAP signal that varies excessively
above or below the calculated value, DTC P0106 will set.
Engine Control Module (ECM)
The engine control module (ECM) is located in the engine
room.
The ECM constantly observes the information from
various sensors. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. It can recognize
operational problems, alert the driver through the MIL
(Service Engine Soon lamp), and store diagnostic trouble
codes (DTCs). DTCs identify the problem areas to aid the
technician in making repairs.
ECM Function
The ECM supplies 5, 12 and 110 volts to power various
sensors or switches. The power is supplied through
resistances in the ECM which are so high in value that a
test light will not light when connected to the circuit. In
some cases, even an ordinary shop voltmeter will not give
an accurate reading because its resistance is too low.
Therefore, a digital voltmeter with at least 10 megohms
input impedance is required to ensure accurate voltage
readings. The ECM controls output circuits such as theinjectors, glow relays, etc., by controlling the ground or
the power feed circuit through transistors or through
either of the following two devices:

Output Driver Module (ODM)

Quad Driver Module (QDM)
ECM Components
The ECM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The ECM
monitors numerous engine and vehicle functions via
electronic sensors such as the crankshaft position (CKP)
sensor, and vehicle speed sensor (VSS). The ECM also
controls certain engine operations through the following:

Fuel injector control

Rail pressure control
ECM Voltage Description
The ECM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
ECM is so high in value that a test light may not illuminate
when connected to the circuit. An ordinary shop
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter to assure accurate
voltage readings.
The input/output devices in the ECM include
analog-to-digital converters, signal buffers, counters,
and special drivers. The ECM controls most components
with electronic switches which complete a ground circuit
when turned ªON.º These switches are arranged in
groups of 4 and 7, called either a surface-mounted quad
driver module (QDM), which can independently control up
to 4 output terminals, or QDMs which can independently
control up to 7 outputs. Not all outputs are always used.
ECM Input/Outputs
Inputs ± Operating Conditions Read

Air Conditioning ªONº or ªOFFº

Engine Coolant Temperature

Crankshaft Position

Electronic Ignition

Manifold Absolute Pressure

Battery Voltage

Intake Throttle Position

Vehicle Speed

Fuel Temperature

Oil Temperature

Intake Air Temperature

EGR boost pressure

Oil rail pressure

Camshaft Position

Accelerator position
Outputs ± Systems Controlled

Exhaust Gas Recirculation (EGR)

Injector Control

QWS

6E±227 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS

QOS

Diagnostics
± Malfunction Indicator Lamp (Service Engine
Soon lamp)
± Data Link Connector (DLC)
± Data Output
ECM Service Precautions
The ECM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the ECM's circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter. The ECM should remain
connected to the ECM or to a recommended breakout
box.
Intake Throttle Position (ITP) Sensor
ITP sensor is a potentiometer type and installed to the
intake throttle valve body. A voltage of 5V is applied
constantly from ECM to ITP sensor thereby to determine
by change in voltage the opening of the intake throttle
valve during warming up.
Transmission Range Switch
IMPORTANT:The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the ECM which position is selected by the
transmission selector lever.
For more information on the transmission on the
transmission range switch, refer to
Automatic
Transmission
.
Accelerator Position Sensor (AP)
AP sensor is a potentiometer type and installed to
accelerator pedal bracket. A voltage of 5V constantly
applied from ECM to the sensor thereby to determine the
accelerator pedaling angle by change in voltage. Further,
this sensor is provided with an accelerator switch, which
is set off only when the accelerator pedal is stepped on.
Aftermarket Electrical and Vacuum
Equipment
Aftermarket (add-on) electrical and vacuum equipment is
defined as any equipment which connects to the vehicle's
electrical or vacuum systems that is installed on a vehicle
after it leaves the factory. No allowances have been
made in the vehicle design for this type of equipment.
NOTE: No add-on vacuum equipment should be added
to this vehicle.
NOTE: A d d - o n e l e c t r i c a l equipment must only be
connected to the vehicle's electrical system at the battery
(power and ground).
Add-on electrical equipment, even when installed to
these guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such asportable telephones and radios. Therefore, the first step
in diagnosing any powertrain problem is to eliminate all
aftermarket electrical equipment from the vehicle. After
this is done, if the problem still exists, it may be diagnosed
in the normal manner.
Electrostatic Discharge Damage
Electronic components used in the ECM are often
designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4000
volts for a person to feel even the zap of a static
discharge.
TS23793
There are several ways for a person to become statically
charged. The most common methods of charging are by
friction and induction.

An example of charging by friction is a person sliding
across a vehicle seat.

Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground. Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity. Static
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.
NOTE: To p r e ve n t p ossible electrostatic discharge
damage, follow these guidelines:

Do not touch the ECM connector pins or soldered
components on the ECM circuit board.

Do not open the replacement part package until the
part is ready to be installed.

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

If the part has been handled while sliding across the
seat, while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.

6E±228
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
General Description (Air Induction)
Air Induction System
The air induction system filters contaminants from the
outside air, and directs the progress of the air as it is
drawn into the engine. A remote-mounted air cleaner
prevents dirt and debris in the air from entering the
engine. The air duct assembly routes filtered air to the
throttle body. Air enters the engine by to following steps:
1. Through the throttle body.
2. Into the intake manifold.
3. Through the cylinder head intake ports.
4. Into the cylinders.
General Description (Fuel Metering)
Deceleration Mode
The ECM reduces the amount of fuel injected when it
detects a decrease in the Accelerator position.
Fuel Injector
Fuel injector comprises the solenoid, hydraulic line, and
fuel line. Fuel injection is controlled by the continuity time
signal and continuity start timing signal from ECM to the
solenoid
ECM determines the running conditions of engine by
input signals such as engine speed. Accelerator throttle
valve opening, and engine coolant temperature, thereby
to send the solenoid the best suited signal to the engine
status. When current is carried to the solenoid, the
armature opens the poppet valve to alow high pressure oil
to run into the injector. Under the pressure of the oil, the
piston and plunger are depressed to compress the fuel in
the combustion chamber of the plunger. Specifically, the
pressure of the fuel compressed is increased by a piston
top/ plunger bottom area ratio over the pressure of high
pressure oil, thereby lifting the fuel nozzle end needle for
injecting fuel.
Fuel Metering System Components
The fuel metering system is made up of the following
parts:

The fuel injectors.

The intake throttle body.

The Accelerator position (AP) sensor

The ECM.

The crankshaft position (CKP) sensor.

The camshaft position (CMP) sensor.
Basic System Operation
Fuel is supplied through fuel filter to the fuel pump.
The fuel pump is installed to the oil pump, and fuel is
forced, through the fuel pump outlet, pipe and cylinder
head inside, into the fuel injector.
An orifice is provided at the rear fuel outlet of cylinder
head to control the pressure of oil.The injector is controlled by ECM which gives
opening/closing commands to the solenoid installed on
the top of the injector. Opening/closing operation of the
pressurized engine oil circuit of the injector controls fuel
injection quantity, fuel injection timing, etc.
A/C Clutch Diagnosis
A/C Request Signal
This signal tells the ECM when the A/C mode is selected
at the A/C control head. The ECM uses this to adjust the
idle speed.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for A/C electrical system.
General Description Exhaust Gas
Recirculation (EGR) System
EGR Purpose
The exhaust gas recirculation (EGR) system is use to
reduce emission levels of oxides of nitrogen (NOx). NOx
emission levels are caused by a high combustion
temperature. The EGR system lowers the NOx emission
levels by decreasing the combustion temperature.
The ECM uses information from the following sensors to
control EGR valve boost pressure.

ECT

ITP

Engine Speed

AP sensor

6H – 2 ENGINE SPEED CONTROL
GENERAL DESCRIPTION


101R200006
Engine control has been changed from the control
cable system to an electronically controlled TP (Throttle
Position) sensor.
The TP sensor is a potentiometer (Variable resistance)
type and installed to the accelerator pedal bracket.
A voltage of 5 V is always applied from the ECM
(Electronic Control Module) to the TP sensor so that the
operating angle of the accelerator pedal can be
detected from a change in voltage.
Further, this sensor is equipped with an accelerator
switch which sends signals to the ECM when the
accelerator pedal is stepped on.
This switch remains on and turns off only when the
accelerator pedal is stepped on.All vehicles have no throttle cable, and therefore, a
return spring is provided on the accelerator pedal and a
return cable assembly having the sliding resistance of a
cable is used to give the pedal a feeling.
To meet the newly adopted electronic control system,
the idling control button has been dropped. Legend
(1) Accerator Position Sensor
(2) Return Cable

WIRING SYSTEM 8DÐ11
Abbreviation Meaning of Abbreviation
A
ABS
ASM
AC
A/C
ACC
A/T
C/B
CSD
DIS
EBCM
ECGI
ECM
ECU
EFE
EGR
4A/T
4WD
FL
FRT
H/L
IC
IGAmpere (S)
Anti-lock brake system
Assembly
Alternating current
Air conditioner
Accessories
Automatic transmission
Circuit breaker
Cold start device
Direct ignition system
Electronic brake control module
Electronic control gasoline injection
Engine control module
Electronic control unit
Early fuel evaporation
Exhaust gas recirculation
4-speed automatic transmission
Four-wheel drive
Fusible link
Front
Headlight
Integrated circuit
IgnitionAbbreviation Meaning of Abbreviation
kW
LH
LWB
M/T
OD
OPT
PCM
QOS
RH
RR
SDM
SRS
ST
STD
SW
SWB
3A/T
V
VSV
W
WOT
W/
W/OKilowatt
Left hand
Long wheel base
Manual transmission
Over drive
Option
Powertrain control module
Quick on start
Right hand
Rear
Sensing and diagnostic module
Supplemental restraint system
Start
Standard
Switch
Short wheel base
3-speed automatic transmission
Volt
Vacuum switching valve
Watt (S)
Wide open throttle
With
Without
Abbreviations

WIRING SYSTEM 8DÐ25
Relay & Fuse Box
FL-1
FL-2 FL-6 FL-5 FL-4 FL-3
F-12 F-11 F-10 F-9 F-8 F-7 F-6 F-5 F-4 F-3 F-2 F-1 RELAY AND FUSE BOX
RHD
FUSIBLE LINK FUSE
MODEL
No.
FL-1
FL-2
FL-3
FL-4
FL-5
FL-6
F-1
F-2
F-3
F-4
F-5
F-6
F-7
F-8
F-9
F-10
F-11
F-12LHD
80A MAIN
50A KEY SW
30A ECM (GASOLINE)
30A CONDENSER FAN
50A GLOW (4JG2)
40A ABS
10A O
2 SENSOR (GASOLINE)
15A HORN HAZARD
15A H/LAMP-LH
15A H/LAMP-RH
15A ANTI-THEFT
20A FOG
20A ABS
15A FUEL PUMP (GASOLINE)
15A TAIL80A MAIN
50A KEY SW
30A ECM (GASOLINE)
30A CONDENSER FAN
50A GLOW (4JG2)
40A ABS
10A O2 SENSOR (GASOLINE)
15A HORN HAZARD
10A H/LAMP-LH (HI)
10A H/LAMP-RH (HI)
10A H/LAMP-LH (LOW)
10A H/LAMP-RH (LOW)
20A FOG
20A ABS
15A FUEL PUMP (GASOLINE)
10A TAIL-LH
10A TAIL-RH —
—
——
810RS027

WIRING SYSTEM 8DÐ27
Relay Location-1 (Relay and Fuse Box)
RHDNo.
X-1
X-2
X-3
X-4
X-5
X-6
X-7
X-8
X-9
X-10
X-11
X-12
X-13
X-16
X-17
X-18
X-19
X-20
X-21
X-22
X-23LHD
RELAY ; LIGHTING
RELAY ; A/C THERMO
RELAY ; COMPRESSOR (GASOLINE)
RELAY ; HORN
RELAY ; TAIL
RELAY ; FUEL PUMP (GASOLINE)
RELAY ; ECM MAIN (GASOLINE)
RELAY ; ANTI-THEFT
RELAY ; STARTER (GASOLINE)
RELAY ; CHARGE (DIESEL)
RELAY ; SHIFT ON THE FLY
RELAY ; CONDENSER FAN
(GASOLINE)
RELAY ; RR FOG LIGHT
RELAY ; FRT FOG LIGHTRELAY ; LIGHTING
RELAY ; DIMMER
RELAY ; A/C THERMO
RELAY ; COMPRESSOR (GASOLINE)
RELAY ; HORN
RELAY ; TAIL
RELAY ; FUEL PUMP (GASOLINE)
RELAY ; ECM MAIN (GASOLINE)
RELAY ; ANTI-THEFT
RELAY ; STARTER (GASOLINE)
RELAY ; CHARGE (DIESEL)
RELAY ; SHIFT ON THE FLY
RELAY ; CONDENSER FAN
RELAY ; FRT FOG LIGHT
—
—
—
—
—
—
—
——
—
—
—
—
—
—
—
X-1
X-2
X-3
X-4X-5
X-6
X-7
X-8X-9
X-10 X-12X-11X-13X-16
X-17X-18
X-19X-20
X-21
X-22
X-23 RELAY AND FUSE BOX
810RS029

WIRING SYSTEM 8DÐ31
Fuse Block Circuit
RHD Models
Indication on label
BOFF
STIG2 ACC
STARTER SW
+
_
O SENSOR (V6)
HORN, HAZARD
H/LAMP-LH
H/LAMP-RH
(FRT . FOG)
ABS
F/ PUMP (V6)
P/ WINDOW, S/ ROOF,
P/SEAT
STARTER RELAY
TURN, BACK
ELEC. IGN.
FRT WIPER & WASHER
RR WIPER & WASHER
H/ LAMP WIPER
ENGINE
IGN. COIL (G)
FUEL CUT (D)
METER, GAUGE
AUDIO(ACC)
MIRROR
CIGAR
STOP, A/T CONT.
AUDIO(B)
TEL(B)
CLOCK(B)
ROOM
RR DEFOG
DOOR LOCK
IG1B
STARTER
C
B
AC GENERATOR
BL
IG
F-1
F-2 10A
F-3 15A
F-4 15A
F-5 15A
F-8 20A
F-9 20A
F-10 15A
C/B-2 30A
C-1 10A
C-3 10A
C-4 10A
C-5 15A
C-6 10A
C-7 10A
C-8 15A
C-9 15A
C-10 10A
C-11 10A
C-12 20A
C-14 15A
C-15 20A
C-16 10A
C-17 25A
C-18 20A RELAY; STARTERCHARGE SIGNAL
FUSE BOX
RELAY; ECM MAIN
FUEL
INJECTOR ECM
HYDRAULIC
UNIT FL-3
30A ECM
FL-6
40A ABS
FL-2
50A KEY SW FL-1
80A MAIN2
2
1
5 W
5 W
8 B/R 5 W
F-6
F-7
F-11
RELAY & FUSE BOX
C-2 15A
BLOWERC-19 25A
C-20 10A
5 W 5 W
5 W
1.25 R
5 W
5 W
3 W
2 R
3 W
3 B/R
3 W
3 W/G
3 B/Y 3 B/Y
5 W 5 W
3 B/W
3 W/B
3 W/B 3 W/B3 W/G 2 W
30 B/R
0.85 B/Y
3 L/B
3 W
1.25 R/G
SFL-2
(DIESEL)
SEAT HEATER
FL-3
40A C/HEATER
FL-5
50A GLOW
CERAMIC HEATER
(DIESEL)
GLOW PLUG
(DIESEL)
31
3 R/B3 W
24
3 W/L
3 R/W
ANTI THEFTC-13 10A
3 B/Y
RELAY: LIGHTING
3 B/R
RELAY; FUEL PUMP
42
TAIL
5 W
2 W
AIR CON
RELAY; HEATER & A/C
24
3 W
3 L/R
C-21 10ASRS
FUSE BOX
C-22 10A
F-12 15A
ECM
D08RV551