parking brake ISUZU AXIOM 2002 Service User Guide

REAR SUSPENSION3D±27

Install the rubber bushing by using installer
J±39214.
NOTE: When mounting rubber bushings, be sure not to
use grease on bushings or any other nearby part.
901RW059
Installation
1. Install trailing link. Make sure that the trailing link is in
its correct position.
NOTE: When mounting trailing link, be sure not to use
grease on bushings or any other nearby part.
460RW011
2. Install bolt, nut and protector. Tighten the bolts and
nuts lightly, then retighten them to the specified
torque after the vehicle is at curb height.
Torque: 137 N´m (101 lb ft)
3. Install parking brake cable.
CAUTION: The parking brake cable should not be
overstrained or slackened.

DIFFERENTIAL (REAR)4A2±5
Axle Housing
Axle Housing and Associated Parts
420RW030
Legend
(1) Lower Link
(2) Stabilizer
(3) Upper Link
(4) Rear Propeller shaft
(5) Shock Absorber(6) Lateral Rod
(7) Brake Hose
(8) Coil Spring
(9) Parking Cable
(10) Axle Assembly
Removal
1. Raise the vehicle and support it with suitable safety
stands.
The hoist must remain under the rear axle housing.
2. Take out brake fluid. Refer to
Hydraulic Brakes in
Brake
section.
3. Remove rear wheels and tires. Refer to
Wheel
Replacement in Suspension
section.
4. Remove propeller shaft. Refer to
Rear Propeller
Shaft
in this section.
5. Drain the rear axle oil into a proper container.
6. Remove parking brake cable, release the connection
between the cable fixing clip equalizer. Refer to
Parking Brakes in Brake section.
7. Move the clip aside and pull out the breather hose.
8. Disconnect the ABS connectors (1) and remove the
brackets attached to the frame and center link.
350RW023

DIFFERENTIAL (REAR)4A2±7
Installation
1. Install brake pipe.
2. Connect Antilock brake system (ABS) speed sensor
and harness, refer to
4±Wheel Anti±Lock Brake
System (ABS) in Brake
section.
3. Install brake disc.
4. Install brake caliper. Refer to
Disk Brakes in Brake
section.
5. Install axle housing assembly.
6. Install coil spring and insulator.
7. Install the lower link fixing bolt and nut to the axle
housing. For the procedures in items 7±11, refer to
Suspension section.
8. Install the upper link bolt and nut to the axle housing.9. Install the lateral rod fixing nut and bolt to the frame
side.
10. Install the stabilizer linkage mounting nut and bolt to
the frame side.
11. Install the shock absorber.
12. Install brake tube flare nut, Refer to
Disk Brakes in
Brake
section.
13. Install ABS connector and bracket.
14. Connect breather hose.
15. Install parking brake cable, Refer to
Parking Brakes in
Brake
section.
16. Bleed brakes. Refer to
Hydraulic Brakes in Brake
section.
Axle Shaft, Oil Seal and Bearing
Axle Shaft and Associated Parts
Disc Brake Model
420RW008
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut
Drum Brake Model
420RX001
Legend
(1) Axle Shaft
(2) Backing Plate
(3) Oil Seal
(4) Bearing
(5) Axle Housing
(6) Lock Washer
(7) Nut

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

4C±29 DRIVE SHAFT SYSTEM
Propeller Shaft
General Description
401R200001
Legend
(1) Front Propeller Shaft
(2) Rear Propeller Shaft;
Aluminum Tube with Flange Yoke Type (for
4y2 model)
(3) Rear Propeller Shaft;
Steel Tube Type (for 4y4 model)
Torque is transmitted from the transmission to the axle
through the propeller shaft and universal joint assembles.
All propeller shafts are the balanced tubular type. A
splined slip joint is provided in some drivelines.

Since the propeller shaft is balanced carefully,
welding or any other modification is not permitted.

Alignment marks should be applied to each propeller
shaft before removal.
Park, turn the engine off and apply the parking brake
to secure the vehicle.

Carefully attach the propeller shaft to the vise, do not
overtighten the vise when securing the propeller
shaft, this may cause deformation.

4C±31 DRIVE SHAFT SYSTEM
Front Propeller Shaft and Associated Parts
401R200006
Legend
(1) Bolt, and Washer (Front Axle Side)
(2) Front Propeller Shaft (with TOD)(3) Bolt and Washer (Transfer Side)
(4) BJ Constant Velocity Joint
(5) LJ Constant Velocity Joint
Removal
1. Jack up the vehicle and support it on the chassis
stands.
2. Gear shift lever should be placed in neutral position
and parking brake released.
3. Remove the exhaust and transfer protectors.
NOTE: Apply alignment marks on the flange at the front
propeller shaft both front and rear side.
401RS020

4C±69 DRIVE SHAFT SYSTEM
Propeller Shaft
General Description
401RX002
Legend
(1) Front Propeller Shaft
(2) Rear Propeller Shaft;
Aluminum Tube with Spline Yoke Type(3) Rear Propeller Shaft;
Aluminum Tube with Flange Yoke Type
(4) Rear Propeller Shaft;
Steel Tube Type (for 4y4, 6VD1, A/T model)
Torque is transmitted from the transmission to the axle
through the propeller shaft and universal joint assembles.
All propeller shafts are the balanced tubular type. A
splined slip joint is provided in some drivelines.

Since the propeller shaft is balanced carefully,
welding or any other modification is not permitted.
Alignment marks should be applied to each propeller
shaft before removal.

Park, turn the engine off and apply the parking brake
to secure the vehicle.

Carefully attach the propeller shaft to the vise, do not
overtighten the vise when securing the propeller
shaft, this may cause deformation.

5A±1
BRAKE CONTROL SYSTEM
AXIOM
BRAKES
CONTENTS
Brake Control System 5A±1. . . . . . . . . . . . . . . . . . . .
Anti±lock Brake System 5B±1. . . . . . . . . . . . . . . . . .
Power±assisted Brake System 5C±1. . . . . . . . . . . .
Parking Brakes (4x4 Model) 5D1±1. . . . . . . . . . . . . .
Parking Brakes (4x2 Model) 5D2±1. . . . . . . . . . . . . .
Brake Control System
CONTENTS
Service Precaution 5A±2. . . . . . . . . . . . . . . . . . . . . .
General Description 5A±3. . . . . . . . . . . . . . . . . . . . .
Functional Description 5A±4. . . . . . . . . . . . . . . . .
System Components 5A±10. . . . . . . . . . . . . . . . . . .
Electronic Hydraulic Control Unit (EHCU) 5A±10.
ABS Warning Light 5A±10. . . . . . . . . . . . . . . . . . . .
Wheel Speed Sensor 5A±10. . . . . . . . . . . . . . . . . .
G-Sensor 5A±10. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal and Anti-lock Braking 5A±10. . . . . . . . . . .
Brake Pedal Travel 5A±10. . . . . . . . . . . . . . . . . . . .
Acronyms and Abbreviations 5A±11. . . . . . . . . . . .
General Diagnosis 5A±11. . . . . . . . . . . . . . . . . . . . . . .
General Information 5A±11. . . . . . . . . . . . . . . . . . . .
ABS Service Precautions 5A±11. . . . . . . . . . . . . . .
Computer System Service Precautions 5A±11. . .
General Service Precautions 5A±11. . . . . . . . . . . .
Note on Intermittents 5A±11. . . . . . . . . . . . . . . . . . .
Test Driving ABS Complaint Vehicles 5A±12. . . . .
ªABSº Warning Light 5A±12. . . . . . . . . . . . . . . . . . .
Normal Operation 5A±12. . . . . . . . . . . . . . . . . . . . .
Tech 2 Scan Tool 5A±13. . . . . . . . . . . . . . . . . . . . . .
DATA LIST 5A±16. . . . . . . . . . . . . . . . . . . . . . . . . . .
ACTUATOR TEST 5A±17. . . . . . . . . . . . . . . . . . . . .
Tech 2 Service Bleed 5A±21. . . . . . . . . . . . . . . . . .
Basic Diagnostic Flow Chart 5A±22. . . . . . . . . . . .
Basic Inspection Procedure 5A±23. . . . . . . . . . . . .
EHCU Connector Pin-out Checks 5A±24. . . . . . . . .
Circuit Diagram 5A±25. . . . . . . . . . . . . . . . . . . . . . .
Connector List 5A±28. . . . . . . . . . . . . . . . . . . . . . . .
Part Location 5A±29. . . . . . . . . . . . . . . . . . . . . . . . .
Symptom Diagnosis 5A±30. . . . . . . . . . . . . . . . . . . . .
Chart A-1 ABS Works Frequently But
Vehicle Does Not Decelerate 5A±30. . . . . . . . . . .
Chart TA-1 ABS Works Frequently But
Vehicle Does Not Decelerate
(Use TECH 2) 5A±31. . . . . . . . . . . . . . . . . . . . . . . .
Chart A-2 Uneven Braking Occurs While
ABS Works 5A±31. . . . . . . . . . . . . . . . . . . . . . . . . . .
Chart TA-2 Uneven Braking Occurs While
ABS Works (Use TECH 2) 5A±31. . . . . . . . . . . . . Chart A-3, TA-3 The Wheels Are Locked 5A±32.
Chart A-4 Brake Pedal Feed Is Abnormal 5A±32.
Chart A-5, TA-5 Braking Sound
(From EHCU) Is Heard While Not Braking 5A±33
Diagnostic Trouble Codes 5A±34. . . . . . . . . . . . . . . .
Diagnosis By ªABSº Warning Light
Illumination Pattern 5A±36. . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes (DTCs) 5A±37. . . . . . .
Chart B-1 With the key in the ON position
(Before starting the engine). Warning light
(W/L) is not activated. 5A±39. . . . . . . . . . . . . . . . .
Chart B-2 CPU Error (DTC 14 (Flash out) /
C0271, C0272, C0273, C0284 (Serial
communications)) 5A±39. . . . . . . . . . . . . . . . . . . . .
Chart B-3 Low or High Ignition Voltage
(DTC 15 (Flash out) / C0277, 0278 (Serial
communications)) 5A±40. . . . . . . . . . . . . . . . . . . . .
Chart B-4 Excessive Dump Time (DTC 17
(Flash out) / C0269 (Serial
communications)) 5A±40. . . . . . . . . . . . . . . . . . . . .
Chart B-5 Excessive Isolation Time
(DTC 18 (Flash out) / C0274
(Serial communications)) 5A±40. . . . . . . . . . . . . . .
Chart B-6 G-Sensor Output Failure
(DTC 21 (Flash out) / C0276
(Serial communications)) 5A±41. . . . . . . . . . . . . . .
Chart B-7 Brake Switch Failure
(DTC 22 (Flash out) / C0281
(Serial communications)) 5A±41. . . . . . . . . . . . . . .
Chart B-8 2WD Controller in 4WD Vehicle
Controller (DTC 13 (Flash out) / C0285
(Serial communications)), 4WD State Input
Signal Failure (DTC 24 (Flash out) / C0282
(Serial communications)) 5A±42. . . . . . . . . . . . . . .
Chart B-9 Pump Motor Failure
(DTC 32 (Flash out) / C0267, C0268
(Serial communications)) 5A±42. . . . . . . . . . . . . . .
Chart B-10 EHCU Valve Relay Failure
(DTC 35 (Flash out) / C0265, C0266
(Serial communications)) 5A±43. . . . . . . . . . . . . . .
Chart B-11 FL Isolation Solenoid Coil Failure
(DTC 41 (Flash out) / C0245, C0247
(Serial communications)) 5A±43. . . . . . . . . . . . . . .
Chart B-12 FL Dump Solenoid Coil Failure
(DTC 42 (Flash out) / C0246, C0248
(Serial communications)) 5A±43. . . . . . . . . . . . . . .

5A±11
BRAKE CONTROL SYSTEM
Acronyms and Abbreviations
Several acronyms and abbreviations are commonly used
throughout this section:
ABS
Anti-lock Brake System
CIM
Coil Integrated Module
CKT
Circuit
DLC
Data Link Connector
EHCU
Electronic Hydraulic Control Unit
FL
Front Left
FR
Front Right
GEN
Generator
H/U
Hydraulic Unit
MV
Millivolts
RR
Rear
RPS
Revolution per Second
VDC
DC Volts
VA C
AC Volts
W/L
Warning Light
WSS
Wheel Speed Sensor
General Diagnosis
General Information
ABS troubles 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 ToolSome 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 to
observe 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 .

If only the 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
(50A). 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

5C±6
POWER±ASSISTED BRAKE SYSTEM
Diagnosis
Road Testing The Brakes
Brake Test
Brakes should be tested on a dry, clean, reasonably
smooth and level roadway. A true test of brake
performance cannot be made if the roadway is wet,
greasy or covered with loose dirt where all tires do not grip
the road equally. Testing will also be adversely affected if
the roadway is crowned so as to throw the weight of the
vehicle toward wheels on one side or if the roadway is so
rough that wheels tend to bounce. Test the brakes at
different vehicle speeds with both light and heavy pedal
pressure; however, avoid locking the wheels and sliding
the tires. Braking without locking the tires will stop the
vehicle in less distance than braking to a skid (which has
no brake efficiency). More tire to road friction is present
while braking without locking the tires than braking to a
skid.
The standard brake system is designed and balanced to
avoid locking the wheels except at very high deceleration
levels.
It is designed this way because the shortest stopping
distance and best control is achieved without brake
lock±up.
Because of high deceleration capability, a firmer pedal
may be felt at higher deceleration levels.
External Conditions That Affect Brake Performance
1. Tires: Tires having unequal contact and grip on the
road will cause unequal braking. Tires must be
equally inflated, identical in size, and the thread
pattern of right and left tires must be approximately
equal.
2. Vehicle Loading: A heavily loaded vehicle requires
more braking effort.
3. Wheel Alignment: Misalignment of the wheels,
particularly in regard to excessive camber and caster,
will cause the brakes to pull to one side.
Brake Fluid Leaks
With engine running at idle and the transmission in
ªNeutralº, depress the brake pedal and hold a constant
foot pressure on the pedal. If pedal gradually falls away
with the constant pressure, the hydraulic system may be
leaking.
Check the master cylinder fluid level. While a slight drop in
the reservoir level will result from normal lining wear, an
abnormally low level in reservoir indicates a leak in the
system. The hydraulic system may be leaking internally
as well as externally. Refer to
Master Cylinder Inspection.
Also, the system may appear to pass this test but still
have slight leakage. If fluid level is normal, check the
vacuum booster push rod length. If an incorrect length
push rod is found, adjust or replace the push rod. Check
the brake pedal travel and the parking brake adjustment.
When checking the fluid level, the master cylinder fluid
level may be lower than the ªMAXº mark if the front and
rear linings are worn. This is normal.
Warning Light Operation
When the ignition switch is in the START position, the
ªBRAKEº warning light should turn on and go off when the
ignition switch returns to the ON position.
The following conditions will activate the ªBRAKEº light:
1. Parking brake applied. The light should be on
whenever the parking brake is applied and the ignition
switch is on.
2. Low fluid level. A low fluid level in the master cylinder
will turn the ªBRAKEº light on.
3. During engine cranking the ªBRAKEº light should
remain on. This notifies the driver that the warning
circuit is operating properly.