1998 ISUZU TROOPER electrical system

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THIS MALUAL INCLUDES THE FOLLOWING SECTIONS:
6VD1 / 6VE1
SECTION No. CONTRNTS
6A ENGINE MECHANICAL
6B ENGINE COOLING
6C ENGINE FUEL
6D1 ENGINE ELECTRICAL
6D2 IGNITION SYSTEM
6D3 STARTING AND CHARGING SYSTEM
6E ENGINE DRIVEABILITY AND EMISSIONS
6F ENGINE EXHAUST
6G ENGINE LUBRICATION
6H ENGINE SPEED CONTROL SYSTEM
6J INDUCTION

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4JG2
4JX1 SECTION No. CONTRNTS
00 SERVICE INFORMATION
6A ENGINE MECHANICAL
6A2 4JG2-NA / 4JG2-TURBO ENGINE
6B ENGINE COOLING
6C FUEL SYSTEM
6D ENGINE ELECTRICAL
6E -
6F EXHAUST
6G -
SECTION No. CONTRNTS
6A ENGINE MECHANICAL
6B ENGINE COOLING
6C ENGINE FUEL
6D ENGINE ELECTRICAL
6E ENGINE DRIVEABILITY AND EMISSIONS
6F ENGINE EXHAUST
6G ENGINE LUBRICATION
6H ENGINE SPEED CONTROL
6J INDUCTION

AIR CONDITIONING 1B Ð 7
EVAPORATOR
The evaporator cools and dehumidifies the air
before the air enters the vehicle. High-pressure
liquid refrigerant flows through the expansion valve
(1) into the low-pressure area of the evaporator (2).
The heat in the air passing through the evaporator
core is lost to the cooler surface of the core, thereby
cooling the air.
As heat is lost between the air and the evaporator
core surface, moisture in the vehicle condenses on
the outside surface of the evaporator core and is
drained off as water.
When the evaporator malfunctions, the trouble will
show up as inadequate supply of cool air. The
cause is typically a partially plugged core due to
dirt, or a malfunctioning blower motor.
The evaporator core with a laminate louver fin is a
single-sided tank type where only one tank is
provided under the core.
ELECTRONIC THERMOSTAT
The thermostat consists of the thermosensor (1)
and thermostat unit (4) which functions electrically
to reduce the noises being generated while the
system is in operation.
The electronic thermosensor (1) is mounted at the
evaporator core (2) outlet and senses the
temperature of the cool air from the evaporator (3).
Temperature signals are input to the thermostat
unit. This information is compared by the thermo
unit and the results in output to operate the A/C
Thermostat relay and turn the magnetic clutch
ÒONÓ or ÒOFFÓ to prevent evaporator freeze-up.
A characteristic of the sensor is that the resistance
decreases as the temperature increases and the
resistance increases as the temperature decreases.
REFRIGERANT LINE
Restrictions in the refrigerant line will be indicated by:
1. Suction line; A restricted suction line will cause
low suction pressure at the compressor, low
discharge pressure and little or not cooling.
2. Discharge line; A restriction in the discharge line
generally will cause the discharge line to leak.
3. Liquid line; A liquid line restriction will be
evidenced by low discharge and suction
pressure and insufficient cooling.
Refrigerant flexible hoses that have a low
permeability to refrigerant and moisture are used.
These low permeability hoses have a special nylon
layer on the inside.
SERVICE CHARGE VALVES
The charging hoses have a quick-joint type fitting,
to reduce refrigerant loss during removal and
installation.
12
3
4
Reinforcement layer(Polyester) Resin layer(Nylon)
Internal rubber layer
External rubber layer
1
2
874RY00003874RX022

This steering wheel and column repair section
covers the Supplemental Restraint System (SRS)
steering column. The following repair procedures
are specific to SRS Components. When servicing a
vehicle equipped with Supplemental Restraint
System, pay close attention to all WARNINGS and
CAUTIONS.
For detailed explanation about SRS, refer to Section
9J "SUPPLEMENTAL RESTRAINT SYSTEM (SRS)"
of manual.
The steering column has three important features in
addition to the steering function:
1. The column is energy absorbing, designed to
compress in a front-end collision to minimize
the possibility of injury to the driver of the
vehicle.
2. The ignition switch and lock are mounted
conveniently on the column.
3. With the column mounted lock, the ignition
and steering operation can be locked to
prevent theft of the vehicle.
The column may be disassembled and
reassembled. To insure the energy absorbing
action, it is important that the specified screws,
bolts and nuts be used only as designated and that
they are tightened to the specified torque.
When the column is removed from the vehicle, a
sharp blow on the end of steering shaft or shift
lever, leaning on the column assembly, or dropping
the assembly could shear or loosen the fasteners
that maintain column rigidity.
WARNING
THIS VEHICLE HAS A SUPPLEMENTAL RE-
STRAINT SYSTEM (SRS).REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW
IN ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN
YOU ARE PERFORMING SERVICE ON OR NEAR
THE SRS COMPONENTS OR THE SRS WIRING,
REFER TO THE SRS SERVICE INFORM ATION.
FAILURE TO FOLLOW WARNINGS COULD RE-
SULT IN POSSIBLE AIR BAG DEPLOYMENT,
PERSONAL INJURY, OR OTHERWISE UN-
NEEDED SRS SYSTEM REPAIRS.
SAFE HANDLING OF INFLATOR MODULES
REQUIRES FOLLOWING THE PROCEDURES
DESCRIBED BELOW FOR BOTH LIVE AND
DEPLOYED MODULES.
SAFETY PRECAUTIONS MUST BE FOLLOWEDWHEN HANDLING A DEPLOYED AIR BAG AS-
SEMBLY (AIR BAG). AFTER DEPLOYMENT,
THE AIR BAG ASSEMBLY (AIR BAG) SURFACE
MAY CONTAIN A SMALL AMOUNT OF SODIUM
HYDROXIDE, A BY-PRODUCT OF THE DEPLOY-
MENT REACTION, THAT IS IRRITATING TO THE
SKIN AND EYES.MOST OF THE POWDER ON
THE AIR BAG ASSEMBLY (AIR BAG) IS HARM-
LESS. AS A PRECAUTION, WEAR GLOVES
AND SAFETY GLASSES WHEN HANDLING A
DEPLOYED AIR BAG ASSEMBLY, AND WASH
YOUR HANDS WITH MILD SOAP AND WATER
AFTERWARDS.
WHEN CARRYING A LIVE AIR BAG ASSEMBLY,
MAKE SURE THE BAG AND TRIM COVER ARE
POINTED AWAY FROM YOU. NEVER CARRY
AN AIR BAG ASSEMBLY BY THE WIRES OR
CONNECTOR ON THE UNDERSIDE OF MODULE.
IN THE CASE OF AN ACCIDENTAL DEPLOY-
MENT, THE BAG WILL THEN DEPLOY WITH
MINIMAL CHANCE OF INJURY. WHEN PLACING
A LIVE AIR BAG ASSEMBLY ON A BENCH OR
OTHER SURFACE, ALWAYS FACE THE BAG AND
TRIM COVER UP, AWAY FROM THE SURFACE.
NEVER REST A STEERING COLUMN ASSEMBLY
ON THE STEERING WHEEL WITH THE AIR
BAG ASSEMBLY FACE DOWN AND COLUMN
VERTICAL.THIS IS NECESSARY SO THAT A
FREE SPACE IS PROVIDED TO ALLOW THE AIR
BAG ASSEMBLY TO EXPAND IN THE UNLIKELY
EVENT OF ACCIDENTAL DEPLOYMENT. OTHER-
WISE, PERSONAL INJURY COULD RESULT.
TO AVOID DEPLOYMENT WHEN TROUBLE
SHOOTING THE SRS SYSTEM, DO NOT USE
ELECTRICAL TEST EQUIPMENT, SUCH AS
BATTERY-POWERED OR A/C-POWERED VOLT-
METER, OHMMETER, ETC., OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN SPECI-
FIED IN THIS MANUAL. DO NOT USE A NON-
POWERED PROBE-TYPE TESTER.
INSTRUCTIONS IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE PER-
SONAL INJURY MAY RESULT. 2A – 52 SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL & COLUMN
GENERAL DESCRIPTION

4B1±7 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Shift on the Fly System (Push Button Type)
Outline of Shift on the Fly System (Push Button Type)
The shift on the fly system switches between 2 wheel
drive (2WD) and 4 wheel drive (4WD) electrically by
driver's pressing the 4WD switch (push button type) on
instrument panel.
This system controls below operations. (Shifting between
ª4Hº and ª4Lº must be performed by transfer control lever
on the floor.)
1. Shifting the transfer front output gear (Connecting to,
and disconnecting from, front propeller shaft by motor
actuator).2. Retrial of shifting the transfer front output gear.
3. Connecting front wheels to, and disconnecting them
from, the front axles by vacuum actuator.
4. Indicator on instrument panel.
5. 4WD out signal to other Electronic Hydraulic Control
Unit (If anti±lock brake system is equipped).
System Diagrams
412RW050

5A±5 BRAKE CONTROL SYSTEM
FR
Front Right
GEN
Generator
MV
Millivolts
RL
Rear Left
RR
Rear RightRPS
Revolution per Second
VDC
Volts DC
VA C
Volts AC
W/L
Warning Light
WSS
Wheel Speed Sensor
General Diagnosis
General Information
ABS malfunction can be classified into two types, those
which can be detected by the ABS warning light and those
which can be detected as a vehicle abnormality by the
driver.
In either case, locate the fault in accordance with the
ªBASIC DIAGNOSTIC FLOWCHARTº and repair.
Please refer to Section 5C for the diagnosis of
mechanical troubles such as brake noise, brake judder
(brake pedal or vehicle vibration felt when braking),
uneven braking, and parking brake trouble.
ABS Service Precautions
Required Tools and Items:

Box Wrench

Brake Fluid

Special Tool
Some diagnosis procedures in this section require the
installation of a special tool.
J-39200 High Impedance Multimeter
When circuit measurements are requested, use a circuit
tester with high impedance.
Computer System Service Precautions
The Anti-lock Brake System interfaces directly with the
Electronic Hydraulic Control Unit (EHCU) which is a
control computer that is similar in some regards to the
Powertrain Control Module. These modules are designed
to withstand normal current draws associated with
vehicle operation. However, care must be taken to avoid
overloading any of the EHCU circuits. In testing for opens
or shorts, do not ground or apply voltage to any of the
circuits unless instructed to do so by the appropriate
diagnostic procedure. These circuits should only be
tested with a high impedance multimeter (J-39200) or
special tools as described in this section. Power should
never be removed or applied to any control module with
the ignition in the ªONº position.
Before removing or connecting battery cables, fuses or
connectors, always turn the ignition switch to the ªOFFº
position.
General Service Precautions
The following are general precautions which should be
observed when servicing and diagnosing the Anti-lock
Brake System and/or other vehicle systems. Failure toobserve these precautions may result in Anti-lock Brake
System damage.

If welding work is to be performed on the vehicle using
an electric arc welder, the EHCU and valve block
connectors should be disconnected before the
welding operation begins.

The EHCU and valve block connectors should never
be connected or disconnected with the ignition ªONº .

EHCU of the Anti-lock Brake System are not
separately serviceable and must be replaced as
assemblies. Do not disassemble any component
which is designated as non-serviceable in this
Section.

If only rear wheels are rotated using jacks or drum
tester, the system will diagnose a speed sensor
malfunction and the ªABSº warning light will
illuminate. But actually no trouble exists. After
inspection stop the engine once and re-start it, then
make sure that the ªABSº warning light does not
illuminate.
If the battery has been discharged
The engine may stall if the battery has been completely
discharged and the engine is started via jumper cables.
This is because the Anti-lock Brake System (ABS)
requires a large quantity of electricity. In this case, wait
until the battery is recharged, or set the ABS to a
non-operative state by removing the fuse for the ABS
(40A). After the battery has been recharged, stop the
engine and install the ABS fuse. Start the engine again,
and confirm that the ABS warning light does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to
identify an intermittent failure. In such a case duplicating
the system malfunction during a test drive or a good
description of vehicle behavior from the customer may be
helpful in locating a ªmost likelyº failed component or
circuit. The symptom diagnosis chart may also be useful
in isolating the failure. Most intermittent problems are
caused by faulty electrical connections or wiring. When
an intermittent failure is encountered, check suspect
circuits for:

Suspected harness damage.

Poor mating of connector halves or terminals not fully
seated in the connector body (backed out).

Improperly formed or damaged terminals.

5A±38
BRAKE CONTROL SYSTEM
Chart A-5, TA-5 Braking Sound (From EHCU) Is Heard While Not Braking
StepActionYe sNo
1Is this the first time the vehicle is being driven after starting the
engine?It is self checking
sound.
Normal.
Go to Step 2
2Is vehicle speed under 10 km/h (6 mph)?It is self checking
sound.
Normal.
Go to Step 3
3Check for the following condition:

At the time of shift down or clutch operation.

At the time of low
drive (ice or snow road) or rough road drive.

At the time of high-speed turn.

At the time of passing curb.

At the time of operating electrical equipment switches.

At the time of racing the engine (over 5000 rpm).
Did it occur under any one condition above?
ABS may
sometime be
actuated even
when brake pedal
is not applied.
Go to Step 4
4Is there play in each sensor/wheel speed sensor rings?
Go to Step 5
Repair.
Go to Step 7
5Damage or powdered iron sticking to each sensor/wheel speed
sensor ring?
Go to Step 6
Repair.
Go to Step 7
6Is each sensor output normal?(Refer to chart C-1 or TC-1).Check harness/
connector for
suspected
disconnection.
If no
disconnection is
found, replace
EHCU.
Go to Step 7
Repair.
Go to Step 7
7Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chart.º
Go to Step 7

5C – 38 POWER ASSISTED BRAKE SYSTEM
FLUID RESERVOIR TANK
2
4
13
Removal Steps
1. Electrical connector
2. Retainer
3. Fluid reservoir
4. O-ring
Installation Steps
To install, follow the removal steps in the
reverse order.
REMOVAL
NOTE:
Before removing fluid reservoir, remove brake fluid
from fluid reservoir.
1. Electrical Connector
2. Retainer
3. Fluid Reservoir
•The fluid level sensor is built into the fluid
reservoir. It cannot be removed for servicing.
4. O-ring
INSTALLATION
To install, follow the removal steps in the reverse
order, noting the following points;
4. O-ring
•O-ring must be set onto the fluid reservoir, before
installing fluid reservoir.
Retainer
Fluid reservoir
O-ring