2002 ISUZU AXIOM four wheel drive

0A±12
GENERAL INFORMATION
Abbreviations Charts
List of automotive abbreviations which may be used
in this manual
A Ð Ampere(s)
ABS Ð Antilock Brake System
AC Ð Alternating Current
A/C Ð Air Conditioning
ACCEL Ð Accelerator
ACC Ð Accessory
ACL Ð Air Cleaner
Adj Ð Adjust
A/F Ð Air Fuel Ratio
AIR Ð Secondary Air Injection System
Alt Ð Altitude
AMP Ð Ampere(s)
ANT Ð Antenna
ASM Ð Assembly
A/T Ð Automatic Transmission/Transaxle
ATDC Ð After Top Dead Center
ATF Ð Automatic Transmission Fluid
Auth Ð Authority
Auto Ð Automatic
BARO Ð Barometric Pressure
Bat Ð Battery
B+ Ð Battery Positive Voltage
Bbl Ð Barrel
BHP Ð Brake Horsepower
BPT Ð Backpressure Transducer
BTDC Ð Before Top Dead Center

C Ð Degrees Celsius
CAC Ð Charge Air Cooler
Calif Ð California
cc Ð Cubic Centimeter
CID Ð Cubic Inch Displacement
CKP Ð Crankshaft Position
CL Ð Closed Loop
CLCC Ð Closed Loop Carburetor Control
CMP Ð Camshaft Position
CO Ð Carbon Monoxide
Coax Ð Coaxial
Conn Ð Connector
Conv Ð Converter
Crank Ð Crankshaft
Cu. In. Ð Cubic Inch
CV Ð Constant Velocity
Cyl Ð Cylinder(s)
DI Ð Distributor Ignition
Diff Ð Differential
Dist Ð Distributor
DLC Ð Data Link Connector
DOHC Ð Double Overhead Camshaft
DTC Ð Diagnostic Trouble Code
DTM Ð Diagnostic Test Mode
DTT Ð Diagnostic Test Terminal
DVM Ð Digital Voltmeter (10 meg.)
DVOM Ð Digital Volt Ohmmeter
EBCM Ð Electronic Brake Control Module
ECM Ð Engine Control Module
ECT Ð Engine Coolant Temperature
EEPROM Ð Electronically Erasable Programmable
Read Only Memory
EGR Ð Exhaust Gas Recirculation
EI Ð Electronic Ignition
ETR Ð Electronically Tuned Receiver
EVAP Ð Evaporation EmissionExh Ð Exhaust

F Ð Degrees Fahrenheit
Fed Ð Federal (All States Except Calif.)
FF Ð Front Drive Front Engine
FL Ð Fusible Link
FLW Ð Fusible Link Wire
FP Ð Fuel Pump
FRT Ð Front
ft Ð Foot
FWD Ð Front Wheel Drive
4WD Ð Four Wheel Drive
4 x 4 Ð Four Wheel Drive
4 A/T Ð Four Speed Automatic Transmission/Transaxle
Gal Ð Gallon
GEN Ð Generator
GND Ð Ground
Gov Ð Governor
g Ð Gram
Harn Ð Harness
HC Ð Hydrocarbons
HD Ð Heavy Duty
Hg Ð Hydrargyrum (Mercury)
HiAlt Ð High Altitude
HO2S Ð Heated Oxygen Sensor
HVAC Ð Heater±Vent±Air±Conditioning
IAC Ð Idle Air Control
IAT Ð Intake Air Temperature
IC Ð Integrated Circuit / Ignition Control
ID Ð Identification / Inside Diameter
IGN Ð Ignition
INJ Ð Injection
IP Ð Instrument Panel
IPC Ð Instrument Panel Cluster
Int Ð Intake
ISC Ð Idle Speed Control
J/B Ð Junction Block
kg Ð Kilograms
km Ð Kilometers
km/h Ð Kilometer per Hour
kPa Ð Kilopascals
kV Ð Kilovolts (thousands of volts)
kW Ð Kilowatts
KS Ð Knock Sensor
L Ð Liter
lb ft Ð Foot Pounds
lb in Ð Inch Pounds
LF Ð Left Front
LH Ð Left Hand
LR ÐLeft Rear
LS Ð Left Side
LWB Ð Long Wheel Base
L±4 Ð In±Line Four Cylinder Engine
MAF Ð Mass Air Flow
MAN Ð Manual
MAP Ð Manifold Absolute Pressure
Max Ð Maximum
MC Ð Mixture Control
MFI Ð Multiport Fuel Injection
MIL Ð Malfunction Indicator Lamp
Min Ð Minimum
mm Ð Millimeter
MPG Ð Miles Per Gallon
MPH Ð Miles Per Hour
M/T Ð Manual Transmission/Transaxle
MV Ð Millivolt

WHEEL AND TIRE SYSTEM3E±7
5. Tire cord breakage.
6. High tire temperatures.
7. Reduced handling.
8. Reduced fuel economy.
Unequal pressure on same axle can cause:
1. Uneven braking.
2. Steering lead.
3. Reduced handling.
4. Swerve on acceleration.
Radial Tire Waddle
480R200006Waddle is side-to-side movement at the front and/or rear
of the car. It can be caused by the steel belt not being
straight within the tire, or by excessive lateral runout of the
tire or wheel. It is most noticeable at low speed, about 8
to 48 km/h (5 to 30 mph). It may also cause rough ride at
80 to 113 km/h (50 to 70 mph).
The car can be road tested to see which end of the car has
the faulty tire. If the tire causing the waddle is on the rear,
the rear end of the car will ªwaddleº. From the driver's
seat, it feels as if someone is pushing on the side of the
car.
If the faulty tire is on the front, the waddle is more easily
seen. The front sheet metal appears to be moving back
and forth. It feels as if the driver's seat is the pivot point
in the car.
Another more time-consuming method of determining the
faulty tire is substituting tire and wheel assemblies that
are known to be good. Follow these steps:
1. Drive the car to determine if the waddle is coming
from the front or rear.
2. Install tire and wheel assemblies known to be good
(from a similar car) in place of those on the end of the
car which is waddling. If the waddle cannot be
isolated to front or rear, start with the rear tires.
3. Road test again. If improvement is noted, install the
original tire and wheel assemblies one at a time until
the faulty tire is found. If no improvement is noted,
install tires known to be good in place of all four. Then,
install the originals one at a time until the faulty tire is
found.
Radial Tire Lead/Pull
ªLead/Pullº is vehicle deviation from a straight path, on a
level road with no pressure on the steering wheel.
Lead is usually caused by:
1. Poorly manufactured radial tires.
2. Uneven brake adjustment.
3. Wheel alignment.
The way in which a tire is built can produce lead in a car.
An example of this is placement of the belt. Off-center
belts on radial tires can cause the tire to develop a side
force while rolling straight down the road and the tire will
tend to roll like a cone.
The ªRadial Tire Lead/Pull Correctionº chart should be
used to make sure that front wheel alignment is not mis-
taken for tire lead.
Rear tires will not cause lead/pull.

DIFFERENTIAL (REAR)4A2±3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(50 psi) (for test purposes only). This will change
noise caused by tires but will not affect noise caused
by the rear axle.
Rear axle nose usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal±to±metal contact.7. Make sure that there is no metal±to±metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. In drive under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently ªwow±wowsº at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in the neutral.
Noise may diminish by gentle braking. Jack up the rear
wheels, spin them by hand and listen for noise at the
hubs. Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close±fitting parts when possible.
Adjust pinion and ring gear backlash.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2±2
General Description
412R200008
TOD (Torque on Demand) system is traction state control
system to vehicle.
Transfer Position and Drive Mode
Three drive modes can be selected through operation of
TOD switch and transfer lever.
Transfer Position
TOD SWITCHModeDrive mode
HIGH2HRWDRear wheel drive
TOD4WD
(HIGH)Electronically controlled torque split
four wheel drive
LOW4L4WD
(LOW)Low-speed mechanical lock-up four
wheel drive
The electronic control unit (ECU) judges the signals from
the TOD switch and controls the transfer drive mode and
shift-on-the-fly system status.

4B2±3
DRIVE LINE CONTROL SYSTEM (TOD)
TOD Control
The TOD position usually drives the rear wheels, and
transmits the torque to the front wheels with the help of
electronically controlled torque split mechanism
according to running conditions encountered. The driving
force is directly transmitted to the rear wheels. This force
is split by the transfer and delivered to the front wheels.
The magnitude of the torque transmitted to the front
wheels is controlled by changing the pressing force of the
multi plate disk clutch built in the transfer unit. The
pressing force of the clutch is controlled by changing the
duty ratio to the electromagnetic coil mounted to the rear
of the clutch. When the clutch is completely disengaged,
the rear wheels are driven. When the clutch is completely
engaged, a rigid four wheel drive mode is obtained. The
torque split status is controlled continuously between the
rear wheel and four wheel drive modes. This system
includes front and rear speed sensors, and receives
throttle position sensor and engine speed information
from the PCM, ABS control unit signal, brake switch
signal, and shift motor position information.
The control unit receives signals sent from these sensors
and changes the pressing force of the multi-plate disk
clutch to determine the torque distribution on the front and
rear wheels. Therefore, when the slip of the rear wheels is
increased against the current torque level in the normal
rear wheel drive mode, the control unit detects the slip
condition, determines the optimum torque based on the
feedback control logic, and increases the torque to the
front wheels.
The control unit uses the signal from the throttle position
sensor to predict the future vehicle condition and the
intention of the driver with respect to acceleration and
deceleration, and determines the initial torque distribution
using these data and the information from the speed
sensors.
In case of small circle turning in the parking lot, for
example, the control unit minimizes the clutch pressing
force to restrict a braking phenomenon. When the ABS
becomes active, the control unit optimizes the clutch
pressing force to ensure stable braking.
TOD Indicator Control
The TOD indicator on the instrument panel informs the
driver of the current working status of the transfer unit.
The information is the drive mode (2H, TOD, 4L,
transition). The indicator can display occasional errors
and corresponding error codes.
Abbreviations
ABS Anti-lock Brake System
ADC Axle Disconnect
(Shift on the fly system)
VB Battery Voltage
VIGN Ignition Voltage

4B2±9
DRIVE LINE CONTROL SYSTEM (TOD)
High-Low Shift Motor
F07R200002
Legend
(1) Reduction Hub
(2) Mechanical Lock Sleeve (Including the built-in
Spring)
(3) Lockup Shift Fork
(4) Return Spring
(5) To TOD Control Unit
(6) Fixed Contact Point
(7) Encoder
(8) Worm gear
(9) Rotate
(10) Shift Motor
(11) The shift cam (12) can be turned freely around
the shift shaft (14).(12) Shift Cam
(13) Torsional Spring
(14) Shift Shaft
(15) Shift Rod
(16) High-Low Shift Fork
(17) High
(18) Low
(19) 2H and TOD Position
(20) Direct Four Wheel Drive (4L Position)
(21) Earth
(22) High
(23) Low
(24) High
(25) Low
When the TOD switch is changed to the 4L (or TOD)
position from the TOD (or 4L) position, the TOD control
unit drives the high±low shift motor according to the
signal. The transfer is shifted to low range from high range
(or to high range from low range) by the shift motor.
The high-low shift motor can run, only when the operation
meets the following conditions to prevent an unexpected
shift between high and low range by a operation error.
1. The car stops. (less than 2 km/h or 1.2 mph and less
than 1500 rpm.)2. The AT selector position is neutral.
3. The brake is applied. (brake switch is on.)
The shift motor has a built-in encoder which watches
motor rotation position. The control unit controls the
rotation of the shift motor based on the position code
detected by the encoder.
The encoder position plate turns together with the shift
shaft and switches on or off the current from the 4 (four)
fixed contact points on the case, then the control unit
recognizes the rotation position of the shift motor.

4D2±32
TRANSFER CASE (TOD)
Main Data and Specification
General Specification
TypeElectronically controlled torque split four wheel drive with two wheel
drive.
2WD: Rear two wheel drive
TOD: Electronically controlled torque split four wheel drive.
4L: Low speed mechanical lockup four wheel drive.
Rear drive: Direct drive
Front drive: Chain drive
Low range deceleration: Planetary gear drive
Control systemSwitch control
Gear ratioHigh: 1.000
Low: 2.480
Lubrication systemBuilt-in oil pump
Forced lubrication
Type of lubricantATF DEXRON)±II or III
Oil capacity1.35 liters. (1.43 US.quart)
Clutch discs number13
Planetary gear teeth numberSun gear: 58
Pinion gear: 15
Ring gear: 86

5A±3
BRAKE CONTROL SYSTEM
General Description
The Anti-lock Brake System (ABS) works on all four
wheels. A combination of wheel speed sensor and
Electronic Hydraulic Control Unit (EHCU) can determine
when a wheel is about to stop turning and adjust brake
pressure to maintain best braking.
This system helps the driver maintain greater control of
the vehicle under heavy braking conditions.
NOTE: The Electronic Hydraulic Control Unit (EHCU)
comprises the Hydraulic Unit (H/U) and the coil Integrated
Module.
C05RW004
Legend
(1) Electronic Line
(2) Hydraulic Line
(3) Hydraulic Unit (H/U)(4) Coil Integrated Module
(5) Front Wheel Speed Sensor
(6) Rear Wheel Speed Sensor
(7) Proportioning and Bypass (P&B) Valve