2002 ISUZU AXIOM engine

3F±2INTELLIGENT SUSPENSION
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT 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 INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or
other corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.
General Description
Intellignet suspension control uses a microcomputer as a
control unit to judge running conditions including engine
revolution from Powertrain Control Module, vehicle speed
from vehicle speed sensor, a brake switch signal, and
vertical and lateral G-sensor signal, then sets optimum
damping force so that best running stability can be
achieved.

3F±8INTELLIGENT SUSPENSION
INTERMITTENT CONDITIONS
If the Warning Lamp flashes a diagnostic trouble code as
intermittent, or if after a test drive a DTC does not
reappear though the detection conditions for this DTC are
present: the problem is most likely a faulty electrical
connection or loose wiring. Terminals and grounds should
always be the prime suspect. Intermittents rarely occur
inside sophisticated electronic components such as the
Control Unit.
Use the DTC information to understand which wires and
sensors are involved.
When an intermittent problem is encountered, check
suspect circuits for:
1. Poor terminal to wire connection.
2. Terminals not fully seated in the connector body
(backed out).
3. Improperly formed or damaged terminals.
4. Loose, dirty, or corroded ground connections:
HINT: Any time you have an intermittent in more than
one circuit, check whether the circuits share a
common ground connection.
5. Pinched or damaged wires.
6. Electro-Magnetic Interference (EMI):
HINT: Check that all wires are properly routed away
from spark plug wires, distributor wires, coil, and
generator. Also check for improperly installed
electrical options, such as lights, 2-way radios, etc.
BULB CHECK
When the starter switch is turned on in the normal state,
the Control Unit turns on the Warning Lamp to check the
bulb. After the engine starts, the Warning Lamp turns off.
F03RY00003
DTC CHECK
1. Diagnosis Trouble Codes (DTC) have been identified
by FLASHING CODES.
2. You have written the list of the DTC. The order of the
malfunctions has no meanings for this Control Unit.
Usually only one or two malfunctions should be set for
a given problem.
3. Check directly the DTCs you identified. The DTC are
sorted by number:
DIAGNOSTIC TROUBLE CODES.

3F±16INTELLIGENT SUSPENSION
Diagnostic Trouble Code (DTC)
Identification
DTC No.DTC NAMECODE
MEMORYWARNING
LAMP
2Actuator Coil Over CurrentYe sOFF
3Actuator Coil/Position Sensor Open Circuit or ShortYe sON
4G±Sensor Open Circuit or ShortYe sON
5Vehicle Speed Sensor Open Circuit or ShortYe sOFF
6Stop Lamp Switch Open Circuit, Short or Contact Point TroubleYe sOFF
7Engine Speed Signal Open Circuit or ShortYe sOFF
9Control Unit AbnormalityYe sOFF

INTELLIGENT SUSPENSION3F±23
DTC5 Vehicle Speed Sensor Open Circuit or Short
Circuit Description
Output speed information is provided to the control unit by
the vehicle speed sensor. The vehicle speed sensor
produces a pulsing AC voltage. The AC voltage level and
number of pulses increases as the speed of the vehicle
increases. The control unit then converts the pulsing
voltage to vehicle speed.
Diagnostic Aids

Inspect the wiring for poor electrical connections
between the control unit 48 way connector and the
speed sensor connectors. Look for possible bent,
backed out, deformed, or damaged terminals. Check
for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
DTC5 Vehicle Speed Sensor Open Circuit or Short
StepActionValue(s)Ye sNo
11. Jack up and support the rear axle on the stand.
2. Change the transfer mode to 2WD, using TOD
switch on instrument panel.
3. Shift the transmission lever in a forward position
and rotate the rear wheels.
Does the speedo-meter operate?
ÐGo to Step 2Go to Step 3
21. Open the throttle and rev up engine speed.
2. Using a volt meter, measure the voltage between
the meter B connector I±23 terminals 7 and 16
(GND).
Does the voltage change alternately at the specified
values?
0V and 12VGo to Step 7Go to Step 5
31. Turn off the starter switch and disconnect the
control connectors C±46 and C±44.
2. Check the continuity between the vehicle speed
sensor connector terminal 3 and meter B connector
I±23 terminal 7.
Is there continuity?
ÐGo to Step 4Go to Step 6
41. Check the continuity between the control unit
connector C±46 terminal 1 and control unit
connector C±44 terminal 48.
Is there continuity?
ÐGo to Step 5Go to Step 6
5Repair or replace the vehicle speed sensor.
ÐGo to Step 8Ð
6Repair the circuit between the vehicle speed sensor
connector terminal 3 and the meter B connector I±23
terminal 7 or the circuit between the control unit
connector C±44 terminal 48 and the speed sensor
connector terminal 3.
ÐGo to Step 8Ð

INTELLIGENT SUSPENSION3F±25
DTC6 Stop Lamp Switch Open Circuit or Short
Circuit Description
The brake switch is used to indicate brake pedal status.
The normally opened brake switch signal voltage circuit is
opened.
Brake switch supplies a B+ signal on circuit RED to the
control unit when the brakes are applied. The control unit
uses this signal to work dive control when the brakes are
applied.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the control unit and brake switch. Look for possible
bent, backed out, deformed or damaged terminals.
Check for weak terminal tension as well. Also check
for a chafed wire that could short to bare metal or
other wiring. Inspect for a broken wire inside the
insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check customer driving habits and/or unusual driving
conditions (i.e. stop and go, highway).

Check brake switch for proper mounting and
adjustment.
DTC6 Stop Lamp Switch Open Circuit or Short
StepActionValue(s)Ye sNo
11. With the engine ªoffº, turn the ignition switch ªonº. If
ABS code is set, check applicable fuse.
2. Apply then release the brake pedal.
Does the brake lamp come on when the brake pedal is
applied and does it come off when the brake pedal is
released?
Ð
Go to
Diagnostic
Aids
Go to Step 2
21. Connect the test light to ground.
2. Back probe ignition feed circuit terminal I±31
terminal 1 at the brake switch.
Is the test light ªonº?
ÐGo to Step 3Go to Step 4
31. Connect the test light to ground.
2. Back probe circuit terminal I±31 terminal 4 at the
brake switch.
Is the test light ªoffº?
ÐGo to Step 7Go to Step 5
4Repair the open in battery feed circuit terminal I±31
terminal 1 to the brake switch.
If fuse is open, check circuit terminal I±31 terminal 4 for
a short to ground.
Is the replacement complete?
ÐGo to Step 13Ð
5Disconnect brake switch connector I±31 and ignition
switch ªonº.
Is the test light ªonº?
ÐGo to Step 8Go to Step 6
6Check the brake switch short (I±31 terminal 1 and I±31
terminal 4).
Was a problem found?
ÐGo to Step 9Go to Step 10
7Check circuit terminal I±31 terminal 4 for a short to
voltage.
Ignition switch ªonº.
Is the test light ªonº?
ÐGo to Step 8Go to Step 10
81. Disconnect the control unit connector C±44.
2. Check circuit terminal I±31 terminal 4 for a short to
voltage.
Was a problem found?
ÐGo to Step 13Go to Step 10

INTELLIGENT SUSPENSION3F±27
DTC7 Engine Speed Signal Open Circuit or Short
Circuit Description
PCM (Powertrain Control Module) converts signals from
the crankshaft position sensor into the engine speed
signals (pulse) and sends these to the control unit and
tachometer.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the control unit connector. Look for possible bent,
backed out, deformed, or damaged terminals. Check
for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check harness routing for a potential short to ground
in circuit BLK/RED.
DTC7 Engine Speed Signal Open Circuit or Short
StepActionValue(s)Ye sNo
1NOTE: Confirm that DTC P0336 or P0337 does not
exist.
If either exists, warning lamps, ªCHECK ENGINEº and
ªCHECK TRANSº are turned on. Repair the engine,
referring to section 6E
Driveability and Emission.
1. Turn on the starter switch.
2. Start the engine.
3. Open the throttle and rev up engine speed.
Does the tachometer operate according to engine
speed?
ÐGo to Step 3Go to Step 2
2Repair the tachometer, referring to section 8D Wiring
System in Body and Accessories
.
ÐGo to Step 6Ð
31. Turn off the starter switch.
2. Check continuity between the control unit connector
C±44 terminal 59 and PCM connector E±34
terminal F7.
Is there continuity ?
ÐGo to Step 4Go to Step 5
4Replace the control unit.
ÐGo to Step 6Ð
5Repair the circuit.
ÐGo to Step 6Ð
61. Reconnect all components, ensure all components
are properly mounted.
2. Clear the DTC.
3. Conduct a test drive.
Has the last test failed or does the current DTC exist?
Ð
Begin diagnosis
again
Go to
Step 1
Repair
verified

4A2±2DIFFERNTIAL (REAR)
General Description
The rear axle assembly is of the semi±floating type in
which the vehicle weight is carried on the axle housing .
The center line of the pinion gear is below the center line
of the ring gear (hypoid drive).
All parts necessary to transmit power from the propeller
shaft to the rear wheels are enclosed in a salisbury type
axle housing (a carrier casting with tubes pressed and
welded into the carrier). A removable aluminum cover at
the rear of the axle housing permits rear axle service
without removal of the entire assembly from the vehicle.
The 8.9 inch ring gear rear axle uses a conventional ring
and pinion gear set to transmit the driving force of the
engine to the rear wheels. This gear set transfers this
driving force at a 90 degree angle from the propeller shaft
to the drive shafts.
The axle shafts are supported at the wheel end of the
shaft by a roller bearing.
The pinion gear is supported by two tapered roller
bearings. The pinion depth is set by a shim pack located
between the gear end of the pinion and the roller bearing
that is pressed onto the pinion. The pinion bearing
preload is set by crushing a collapsible spacer between
the bearings in the axle housing.
The ring gear is bolted onto the differential case with 10
bolts.
The differential case is supported in the axle housing by
two tapered roller bearings. The differential and ring gear
are located in relationship to the pinion by using selective
shims and spacers between the bearing and the
differential case. To move the ring gear, shims are deleted
from one side and an equal amount are added to the other
side. These shims are also used to preload the bearings
which are pressed onto the differential case. Two bearing
caps are used to hold the differential into the rear axle
housing.
The differential is used to allow the wheels to turn at
different rates of speed while the rear axle continues to
transmit the driving force. This prevents tire scuffing
when going around corners and prevents premature wear
on internal axle parts.
The rear axle is sealed with a pinion seal, a seal at each
axle shaft end, and by a liquid gasket between the rear
cover and the axle housing.
Limited Slip Differential (LSD)
The axle assembly may be equipped with an limited slip
differential (LSD). It is similar to the standard differential
except that part of the torque from the ring gear is
transmitted through clutch packs between the side gears
and differential case.
The LSD construction permits differential action when
required for turning corners and transmits equal torque to
both wheels when driving straight ahead. However, when
one wheel tries to spin due to a patch of ice, etc., the
clutch packs automatically provide more torque to the
wheel which is not trying to spin.
In diagnosing customer complaints, it is important to
recognize two things:
1. If, both wheels slip, with unequal traction, the LSD
has done all it can possibly do.
2. In extreame cases of differences in traction, the
wheel with the least traction may spin after the LSD
has transferred as much torque as possible to the
non-slipping wheel.
Limited Slip Differntials impose additional requirements
on lubricants, and require a special lubricant or lubricant
additive. Use 80W90 GL±5 LSD lubricant.
Rear Axle Identification
The Bill of Material and build date information(1) is
stamped on the right axle tube on the rearward side.
The axle ratio is identified by a tag(3) which is secured by
a cover bolt. If the axle has limited-slip differntial, it also
will be identified with a tag(2) secured by a cover bolt.
425RX001

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.