2002 ISUZU AXIOM light

5A±50BRAKE CONTROL SYSTEM
Chart B-22 Rear Speed Sensor Missing Signal (DTC 63 (Flash out) / C0236, C0237 (Serial
communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the Rear speed sensor resistance between coil
integrated module connector (C-6) terminals 4 and 12.
Is the resistance between 1.0k and 1.7k ohms?
Go to Step 2Go to Step 3
2Is there play sensor/sensor rotor?Repair.
Go to
Step 6Go to Step 4
3Measure the rear speed sensor resistance at the sensor
connector.
Is the resistance between 1.0k and 1.7k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 6
Replace sensor.
Go to
Step 6
4Damage and powered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 5
5Is sensor output normal? (Chart C-1-3 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 6
Replace sensor.
Go to
Step 6
61. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chartº
Go to Step 6
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the vehicle is at a stop. Turn
the ignition switch to the ON position and drive the vehicle
at 12 km/h (8 mph) or higher to make sure that the
warning light goes out.

5A±51
BRAKE CONTROL SYSTEM
Chart B-23 Simultaneous Drop-out of Front Speed Sensor Signal (DTC 64 (Flash out) /
C0229 (Serial communications))
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Measure the FL speed sensor resistance between coil
integrated module connector (C-6) terminals 2 and 10.
Is the resistance between 2.0k and 2.8k ohms?
Go to Step 2Go to Step 3
2Measure the FR speed sensor resistance between coil integrated
module connector (C-6) terminals 3 and 11.
Is the resistance between 2.0k and 2.8 k ohms?
Go to Step 5Go to Step 4
3Measure the FL speed sensor resistance at the sensor connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 2
Replace sensor.
Go to
Step 2
4Measure the FR speed sensor resistance at the sensor
connector.
Is the resistance between 2.0k and 2.8k ohms?Repair harness
abnormality
between sensors
and coil
integrated
module.
Go to
Step 5
Replace sensor.
Go to
Step 5
5Damage and powered iron sticking to sensor/sensor ring?Repair.
Go to
Step 6Go to Step 6
6Is there play sensor/sensor rotor?Repair.
Go to
Step 7Go to Step 7
7Is sensor output normal? (Chart C-1-1&C-1-2 or TC-1)Check for faults
in harness
between speed
sensor and coil
integrated
module.
Fault found:
repair, and
perform system
self-check.
No fault found:
replace EHCU.
Go to
Step 8
Replace sensor.
Go to
Step 8
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat ªBasic
diagnostic flow
chartº
Go to Step 8
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the vehicle is at a stop. Turn
the ignition switch to the ON position and drive the vehicle
at 12 km/h (8 mph) or higher to make sure that the
warning light goes out.

5A±52BRAKE CONTROL SYSTEM
Chart B-24 Wheel Speed Input Abnormality (DTC 65 (Flash out) / C0238 (Serial
communications))
StepActionYe sNo
1Using TECH 2?Go to Step 2Go to Step 3
21. Connect TECH 2.
2. Select Snap shot manual trigger.
3. With wheel speed data displayed, run the vehicle when speed
has arrived at 30 km/h (18 mph).
4. Check speed data on each wheel (refer to the criterion given
below). * 1
Is the abnormal sensor condition found?
Replace.
Go to
Step 8
Go to Step 3
All the sensors
should follow the
following
flowchart (without
using TECH 2).
3Is there play in sensor/sensor ring?Repair.
Go to
Step 8Go to Step 4
4Is there powdered iron sticking to sensor/sensor ring?Repair.
Go to
Step 8Go to Step 5
5Is there a broken tooth or indentation in sensor ring?Replace sensor
ring.
Go to
Step 8Go to Step 6
6Is there play in wheel bearing?Adjust or repair.
Go to
Step 8Go to Step 7
7Is the check wiring between sensor and coil integrated module
normal?
Replace EHCU.
Go to
Step 8
Repair, and
perform system
self-check.
Go to
Step 8
81. Reconnect all components, ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat `Basic
diagnostic flow
chartº
Go to Step 8
Sensor Signal Abnormality Criteria using TECH 2
1. While driving, the speed of one or two wheels is 25%
or more higher or lower than that of the other wheels.
2. The speed of one or two wheels is 10 km/h (6 mph) or
more higher or lower than that of the other wheels.
3. During steady driving, wheel speed changes abruptly.
*1 The vehicle must run on a level paved road.
NOTE: Even after repairing the faulty part the warning
light (W/L) does not go out if the vehicle is at a stop.
Turn the ignition switch to the ON position and drive the
vehicle at 12 km/h (8 mph) or higher to make sure that the
warning light goes out.
It is important to verify that the correct tires are installed
on vehicle.

5A±53
BRAKE CONTROL SYSTEM
Unit Inspection Procedure
This section describes the following inspection
procedures referred to during
Symptom Diagnosis and
Diagnosis By ªABSº Warning Light Illumination Pattern
without TECH 2with TECH 2
Sensor Output InspectionChart C-1-1 to C-1-3Chart TC-1
Chart C-1-1 FL Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect coil integrated module connector.
3. Jack up the vehicle with all four wheels off the ground.
Measure the AC voltage between coil integrated module
connector terminals while turning FL wheel at a speed of 1
RPS:
Is the voltage between coil integrated module connector (C-6)
terminals 2 and 10 less than 200 mV?
Go to Step 2
OK.
Go to
Step 3
21. Disconnect the wheel speed sensor.
2. Measure resistance between the wheel speed sensor
connector terminals 1 and 2.
Is the check between connector (C-28) terminals 1 and 2 within
2.0k - 2.8k ohms?Connector is
faulty, or open or
short circuit of
harness between
wheel speed
sensor connector
and coil
integrated
module.
Inspect and
correct the
connector or
harness.
Go to
Step 3
Wheel speed
sensor is faulty.
Replace the
wheel speed
sensor.
Go to
Step 3
3Reconnect all components, ensure all components are properly
mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chartº
Go to Step 3

5C±1 POWER±ASSISTED BRAKE SYSTEM
AXIOM (Vehicles Produced Before July/31/2001)
BRAKES
POWER-ASSISTED BRAKE SYSTEM
CONTENTS
Service Precaution 5C±2. . . . . . . . . . . . . . . . . . . . . .
General Description 5C±2. . . . . . . . . . . . . . . . . . . . .
Diagnosis 5C±6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Diagnosis 5C±7. . . . . . . . . . . . . . . . . . . . . . .
Hydraulic Brakes 5C±10. . . . . . . . . . . . . . . . . . . . . . . .
Filling Master Cylinder Reservoir 5C±10. . . . . . . .
Deterioration of Brake Fluid 5C±10. . . . . . . . . . . . .
Leakage of Brake Fluid 5C±10. . . . . . . . . . . . . . . . .
Bleeding Brake Hydraulic System 5C±10. . . . . . . .
Flushing Brake Hydraulic System 5C±11. . . . . . . .
Brake Pipes and Hoses 5C±11. . . . . . . . . . . . . . . .
Brake Hose Inspection 5C±11. . . . . . . . . . . . . . . . .
Front Caliper Brake Hose 5C±12. . . . . . . . . . . . . . . .
Front Caliper Brake Hose and Associated
Parts 5C±12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±12. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±12. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Axle Brake Hose 5C±13. . . . . . . . . . . . . . . . . . .
Rear Axle Brake Hose and Associated
Parts 5C±13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±13. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±13. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Pipe 5C±14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±14. . . . . . . . . . . . . . . . . . . . . . . . . . . .
P & B (Proportioning and Bypass) Valve 5C±15. . . .
P & B (Proportioning and Bypass) Valve
Sectional View 5C±15. . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±15. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±15. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±16. . . . . . . . . . . . .
Brake Pedal 5C±17. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking Pedal Height 5C±17. . . . . . . . . . . . . . . . .
Checking Pedal Travel 5C±17. . . . . . . . . . . . . . . . .
Brake Pedal and Associated Parts 5C±18. . . . . . .
Removal 5C±18. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±18. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stoplight Switch 5C±19. . . . . . . . . . . . . . . . . . . . . . . . .
Parts Location 5C±19. . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±19. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±19. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±20. . . . . . . . . . . . .
Fluid Reservoir Tank 5C±21. . . . . . . . . . . . . . . . . . . . .
Fluid Reservoir Tank and Associated Parts 5C±21Removal 5C±21. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±21. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Master Cylinder Assembly 5C±22. . . . . . . . . . . . . . . .
Master Cylinder Assembly and Associated
Parts 5C±22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±22. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±22. . . . . . . . . . . . . . . . . .
Installation 5C±23. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±24. . . . . . . . . . .
Special Tools 5C±24. . . . . . . . . . . . . . . . . . . . . . . . . .
Vacuum Booster Assembly 5C±25. . . . . . . . . . . . . . .
Vacuum Booster Assembly and Associated
Parts 5C±25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±25. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±26. . . . . . . . . . . . . . . . . .
Installation 5C±26. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exterior Components 5C±28. . . . . . . . . . . . . . . . . . . .
Exterior Components and Associated Parts 5C±28
Removal 5C±28. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5C±29. . . . . . . . . . . . . . . . . .
Installation 5C±29. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vacuum Booster Overhaul 5C±29. . . . . . . . . . . . . . . .
Vacuum Booster 5C±29. . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 5C±30. . . . . . . . . . . . .
Special Tools 5C±31. . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Disc Brake Pads 5C±32. . . . . . . . . . . . . . . . . . .
Front Disc Brake Pads Inspection 5C±32. . . . . . . .
Front Disc Brake Pads and Associated
Parts 5C±32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5C±33. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±33. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Disc Brake Rotor 5C±35. . . . . . . . . . . . . . . . . . .
Inspection 5C±35. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Brake Rotors 5C±35. . . . . . . . . . . . . . . .
Refinishing Brake Rotors 5C±35. . . . . . . . . . . . . . .
Front Disc Brake Caliper Assembly 5C±36. . . . . . . .
Front Disc Brake Caliper Assembly and
Associated Parts 5C±36. . . . . . . . . . . . . . . . . . . . . .
Removal 5C±37. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5C±37. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Disc Brake Caliper 5C±39. . . . . . . . . . . . . . . . .
Front Disc Brake Caliper Disassembled
View 5C±39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembly 5C±39. . . . . . . . . . . . . . . . . . . . . . . . . .

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.

5C±7 POWER±ASSISTED BRAKE SYSTEM
General Diagnosis
ConditionPossible causeCorrection
Brake PullTire inflation pressure is unequal.Adjust
Front wheel alignment is incorrect.Adjust
Unmatched tires on same axle.Tires with approx. the same amount
of tread should be used on the same
axle.
Restricted brake pipes or hoses.Check for soft hoses and damaged
lines. Replace with new hoses and
new doubleªwalled steel brake
piping.
Water or oil on the brake pads.Clean or replace.
Brake pads hardened.Replace
Brake pads worn excessively.Replace
Brake rotor worn or scored.Grind or replace.
Disc brake caliper malfunctioning.Clean or replace.
Front hub bearing preload incorrect.Adjust or replace.
Loose suspension parts.Check all suspension mountings.
Loose calipers.Check and tighten the bolts to
specifications.
Brake Roughness or Chatter
(Pulsates)Excessive lateral runout.Check per instructions. If not within
specifications, replace or machine
the rotor.
Parallelism not within specifications.Check per instructions. If not within
specifications, replace or machine
the rotor.
Wheel bearings not adjusted.Adjust wheel bearings to correct
specifications
Pad reversed (steel against iron).Replace the brake pad and machine
rotor to within specifications.
Excessive Pedal EffortMalfunctioning vacuum booster.Check the vacuum booster operation
and repair, if necessary.
Partial system failure.Check the front and rear brake
system for failure and repair. Also,
check the brake warning light. If a
failed system is found, the light
should indicate failure.
Excessively worn pad.Check and replace pads in sets.
Piston in caliper stuck or sluggish.Remove caliper and rebuild.
Fading brakes due to incorrect pad.Remove and replace with original
equipment pad or equivalent.
Vacuum leak to vacuum booster.Check for ruptured or loose hose.
Check the direction of check valve
within vacuum hose.Correct vacuum hose direction.
Grease on the brake pads.Replace or clean.

5C±8
POWER±ASSISTED BRAKE SYSTEM
Condition CorrectionPossible cause
Excessive Brake Pedal TravelAir in hydraulic circuit.Bleed the hydraulic circuit.
Level of brake fluid in the reservoir
too low.Replenish brake fluid reservoir to
specified level and bleed hydraulic
circuit as necessary.
Master cylinder push rod clearance
excessive.Adjust
Leakage in hydraulic system.Correct or replace defective parts.
Brake DragMaster cylinder pistons not returning
correctly.Adjust the stop light switch and
vacuum booster push rod. If
necessary, rebuild.
Restricted brake pipes or hoses.Check for soft hoses or damaged
pipes, and replace with new hoses
and new double±walled steel brake
piping.
Parking brake maladjusted.Adjust
Parking brake lining clearance
insufficient.Adjust
Brake pedal free play insufficient.Adjust the brake pedal height or
power cylinder operating rod.
Piston in the master cylinder sticking.Replace
Piston in the disc brake caliper
sticking.Replace piston seals.
Brake pads sticking in caliper.Clean
Return spring weakened.Replace
Parking brake binding.Overhaul the parking brakes and
correct.
Front hub bearing preload incorrect.Adjust or replace.
Parking brake shoes not returning.Correct or replace the brake back
plate and brake shoe as necessary.
Obstructions in hydraulic circuit.Clean
Rotor warped excessively.Grind or replace.
Rear brake drum distorted.Grind or replace.
Parking cable sticking.Grind or replace.
Grabbing or Uneven Braking Action
(All conditions listed under ªPullsº)Malfunctioning vacuum booster.Check operation and correct as
necessary.
Binding brake pedal mechanism.Check and lubricate, if necessary.
Corroded caliper assembly.Clean and lubricate.
Brake NoisyBrake pads are worn.Replace
Brake pads are hardened.Replace
Brake pads are in poor contact with
rotor.Correct
Brake disc(s) warped, worn or
damaged.Grind or replace.
Disc brake anti±squeak shims
fatigued.Replace
Front hub bearings are loose or
preload is incorrect.Adjust or replace.
Brake disc is rusted.Grind or replace.