warning ISUZU TROOPER 1998 Service Service Manual

5A±53 BRAKE CONTROL SYSTEM
Chart B-21 FR Speed Sensor Short Circuit (DTC 62)
StepActionYe sNo
11. Turn the key off.
2. Disconnect EHCU connector.
3. Measure the FR speed sensor resistance between EHCU
connector terminals 4 and 5.
Is the resistance between 1.3k and 1.9k ohms?
Go to Step 2Go to Step 3
2Is there play in the sensor/sensor rotor?
Go to Step 4
Repair.
Go to Step 6
3Measure the FR speed sensor resistance at the sensor
connector.
Is the resistance between 1.3k and 1.9k ohms?Repair harness
abnormality
between sensors
and EHCU.
Go to Step 6
Replace sensor.
Go to Step 6
4Damage and powdered iron sticking to sensor/sensor ring?
Go to Step 5
Repair.
Go to Step 6
5Is sensor output normal? (Chart C-1-2 or TC-1)Check for faults
in harness
between speed
sensor and
EHCU.
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 and ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat ªBasic
diagnostic flow
chart.º
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 or higher to make sure that the warning light
goes out.

5A±54
BRAKE CONTROL SYSTEM
Chart B-22 RL Speed Sensor Short Circuit (DTC 63)
StepActionYe sNo
11. Turn the key off.
2. Disconnect EHCU connector
3. Measure the RL speed sensor resistance between EHCU
connector terminals 22 and 23.
Is the resistance between 1.3k and 1.9k ohms?
Go to Step 2Go to Step 3
2Is there play in the sensor/sensor rotor?
Go to Step 4
Repair.
Go to Step 6
3Measure the RL speed sensor resistance at the sensor
connector.
Is the resistance between 1.3k and 1.9k ohms?Repair harness
abnormality
between sensors
and EHCU.
Go to Step 6
Replace sensor.
Go to Step 6
4Damage and powdered iron sticking to sensor/sensor ring?
Go to Step 5
Repair.
Go to Step 6
5Is sensor output normal? (Chart C-1-3 or TC-1)?Check for faults
in harness
between speed
sensor and
EHCU.
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 and ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat the ªBasic
diagnostic flow
chart.º
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 or higher to make sure that the warning light
goes out.

5A±55 BRAKE CONTROL SYSTEM
Chart B-23 RR Speed Sensor Short Circuit (DTC 64)
StepActionYe sNo
11. Turn the key off.
2. Disconnect EHCU connector.
3. Measure the RR speed sensor resistance between EHCU
connector terminals 2 and 3.
Is the resistance between 1.3k and 1.9k ohms?
Go to Step 2Go to Step 3
2Is there play in the sensor/sensor rotor?
Go to Step 4
Repair.
Go to Step 6
3Measure the RR speed sensor resistance at the sensor
connector.
Is the resistance between 1.3k and 1.9k ohms?Repair harness
abnormality
between sensors
and EHCU.
Go to Step 6
Replace sensor.
Go to Step 6
4Damage and powdered iron sticking to sensor/sensor ring?
Go to Step 5
Repair.
Go to Step 6
5Is sensor output normal? (Chart C-1-4 or TC-1)Check for faults
in harness
between speed
sensor and
EHCU.
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 and ensure all components are
properly mounted.
2. Clear diagnostic trouble code.
Was this step finished?
Repeat ªBasic
diagnostic flow
chart.º
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 or higher to make sure that the warning light
goes out.

5A±56
BRAKE CONTROL SYSTEM
Chart B-24 Sensor Signal Input Abnormality (DTC 65)
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 8
Go to Step 4
4Is there powdered iron sticking to sensor/sensor ring?Repair.
Go to Step 8
Go to Step 5
5Is there a broken tooth or indentation in sensor ring?Replace sensor
ring.
Go to Step 8
Go to Step 6
6Is there play in wheel bearing?Adjust or repair.
Go to Step 8
Go to Step 7
7Is the check wiring between sensor and EHCU 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 ªBasic
diagnostic flow
chart.º
Go to Step 8
Sensor Signal Abnormality Criteria using
TECH 2
1. While driving, the speed of one or two wheels 25% or
more higher than that of the other wheels.
2. The speed of one or two wheels is 10 km/h (6 mph) or
more higher 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 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±57 BRAKE CONTROL SYSTEM
Unit Inspection Procedure
This section describes the following inspection
procedures referred to during ªSYMPTOM DIAGNOSISº
and ªDIAGNOSIS BY `ABS' WARNING LIGHT
ILLUMINATION PATTERNº :
without TECH 2with TECH 2
Wheel Speed Sensor Output InspectionChart C-1-1 to C-1-4Chart TC-1
Transmission SW InspectionChart C-2Chart TC-2
Chart C-1-1 FL Sensor Output Inspection Procedure
StepActionYe sNo
11. Turn the key off.
2. Disconnect EHCU connector.
3. Jack up the vehicle, With all four wheels off the ground.
Measure the AC voltage between EHCU connector terminals
while turning FL wheel at a speed of 1 RPS:
Is voltage between EHCU connector terminals 20 and 21 under
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 resistance between connector (C-13) terminals 1 and 2 within
1.3k - 1.9k ohms?Connector is
faulty, or open or
short circuit in
harness between
wheel speed
sensor connector
and EHCU.
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 and ensure all components are
properly mounted.
Was this step finished?Repeat the ªBasic
diagnostic flow
chart.º
Go to Step 3

5B±1 ANTI±LOCK BRAKE SYSTEM
BRAKES
ANTI-LOCK BRAKE SYSTEM
CONTENTS
Service Precaution 5B±1. . . . . . . . . . . . . . . . . . . . . .
Electronic Hydraulic Control Unit 5B±2. . . . . . . . . .
Electronic Hydraulic Control Unit and
Associated Parts 5B±2. . . . . . . . . . . . . . . . . . . . . .
Removal 5B±2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 5B±2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
G-Sensor 5B±3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 5B±3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5B±3. . . . . . . . . . . . . . . . . .
Installation 5B±3. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Wheel Speed Sensor 5B±4. . . . . . . . . . . . . . . Front Wheel Speed Sensor and
Associated Parts 5B±4. . . . . . . . . . . . . . . . . . . . . .
Removal 5B±4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5B±5. . . . . . . . . . . . . . . . . .
Installation 5B±5. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Wheel Speed Sensor 5B±6. . . . . . . . . . . . . . .
Rear Wheel Speed Sensor and
Associated Parts 5B±6. . . . . . . . . . . . . . . . . . . . . .
Removal 5B±6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 5B±6. . . . . . . . . . . . . . . . . .
Installation 5B±6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Precaution
WARNING: I F S O E Q U IPPED WITH 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.CAUTION: Re place all components included in
repair kits used to service this system. Lubricate
rubber parts with clean, fresh brake fluid to ease
assembly. Do not use shop air with in±line
lubricators on brake parts, as damage to rubber
components may result. If any hydraulic component
is removed or brake line disconnected, it may be
necessary to bleed part or all of the brake system.
NOTE: The use of rubber hoses or parts other than those
furnished specifically for the Anti±lock Brake System may
lead to functional problems requiring major overhaul.

5C – 2 POWER ASSISTED BRAKE SYSTEM
Front Disc Brakes ........................................................................................................... 5C-47
Brake Pads Replacement .......................................................................................... 5C-47
Caliper Replacement ................................................................................................. 5C-50
Rebuilding the Caliper ............................................................................................... 5C-53
Rear Disc Brakes ............................................................................................................ 5C-56
Brake Pads Replacement .......................................................................................... 5C-56
Caliper Replacement ................................................................................................. 5C-59
Rebuilding the Caliper ............................................................................................... 5C-62
Unit Repair .......................................................................................................................... 5C-65
Master Cylinder .............................................................................................................. 5C-65
Vacuum Booster ............................................................................................................. 5C-67
SERVICE PRECAUTION
WARNING:
IF SO EQUIPPED WITH 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 specification. Following these instructions can help you avoid damage to
parts and systems.

5C – 4 POWER ASSISTED BRAKE SYSTEM
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 low from the “MAX” mark if the
front and rear linings are worn. This is not abnormal.
WARNING LIGHT OPERATION
When the ignition switch is in the START position, the
“BRAKE” warning light should glow and go OFF when
the ignition switch returns to the ON position.
The following conditions will activate the “BRAKE”
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 “BRAKE” light ON.
3. During engine cranking the “BRAKE” light should
remain ON. This notifies the driver that the
warning circuit is operating properly.
4. Low vacuum warning light. The vacuum warning
device is equipped on the diesel engine equipped
vehicles. The “BRAKE” light comes on when the
reserved vacuum is lowered to a critical level or
power brake line is damaged.
NOTE:
Depressing the brake pedal repeatedly may cause the
brake warning light to come ON when the engine is
running at idling speed or at low speed. This is
because the amount of vacuum is used more than
that supplied by the vacuum pump, however, no
problem will occur actually.
If the lamp is still lighting even after 2 or 3 seconds at
idling speed, the vacuum line may be defective.
ANTILOCK BRAKE SYSTEM (ABS)
Refer to Brake Control System for inspection and
diagnosis procedure of the hydraulic unit.

POWER ASSISTED BRAKE SYSTEM 5C – 5
TROUBLESHOOTING
Condition Possible Cause Correction
Brake Pull1. Tire inflation pressures unequal. 1. Adjust
2. Front wheel alignment incorrect. 2. Adjust
3. Unmatched tires on same axle. 3. Tire with approx. the same amount of
tread should be used on the same axle.
4. Restricted brake pipes or hoses. 4. Check for soft hoses and damaged
lines. Replace with new hoses and new
double-walled steel brake piping.
5. Water or oil on brake pads. 5. Clean or replace.
6. Brake pads hardened. 6. Replace.
7. Brake pads worn excessively. 7. Replace.
8. Brake rotor worn or scored. 8. Grind or replace.
9. Disc brake caliper malfunctioning. 9. Clean or replace.
10. Front hub bearing preload incorrect. 10. Adjust or replace.
11. Loose suspension parts. 11. Check all suspension mountings.
12. Loose calipers. 12. Check and tighten bolts to specifications.
Brake 1. Excessive lateral runout. 1. Check per instructions.
Roughness-orIf not within specifications, replace or
Chattermachine the rotor.
(Pulsates)2. Parallelism not within specifications. 2. Check per instructions.
If not within specifications, replace or
machine the rotor.
3. Wheel bearings not adjusted. 3. Adjust wheel bearings to correct
specifications.
4. Pad reversed (steel against iron). 4. Replace brake pad and machine rotor
to within specifications.
Excessive 1. Malfunctioning vacuum booster. 1. Check vacuum booster operation and
Pedal repair, if necessary.
Effort2. Partial system failure. 2. Check front and rear brake system for
failure and repair. Also, check brake
warning light. If a failed system is
found, the light should indicate a
failure.
3. Excessively worn pad. 3. Check and replace pads in sets.
4. Piston in caliper stuck or sluggish. 4. Remove caliper and rebuild.
5. Fading brakes due to incorrect pad. 5. Remove and replace with original
equipment pad or equivalent.
6. Vacuum leak to vacuum booster. 6. Check for ruptured or loose hose.
7. Check direction of check valve within 7. Correct vacuum hose direction.
vacuum hose.
8. Grease on the brake pads. 8. Replace or clean.
Excessive 1. Air in hydraulic circuit. 1. Bleed hydraulic circuit.
Brake Pedal 2. Level of brake fluid in resevoir too low. 2. Replenish brake fluid resevoir to
Travelspecified level and bleed hydraulic
circuit as necessary.
3. Master cylinder push rod clearance 3. Adjust.
excessive.
4. Leakage in hydraulic system. 4. Correct or replace defective parts.

5C – 54 POWER ASSISTED BRAKE SYSTEM
5. Piston
•Insert a block of wood into the caliper and force
out the piston by blowing compressed air into the
caliper at the flexible hose attachment. This
procedure must be done prior to removal of dust
boot.
WARNING:
DO NOT PLACE YOUR FINGERS IN FRONT OF THE
PISTON IN AN ATTEMPT TO CATCH OR PROTECT IT
WHEN APPLYING COMPRESSED AIR. THIS COULD
RESULT IN PERSONAL INJURY.
CAUTION:
Use just enough air to ease the piston out of the
bore. If the piston is blown out, it may be damaged.
6. Dust Boot; Piston
7. Piston Seal
8. Bleeder with Cap
9. Caliper Body
REASSEMBLY
9. Caliper Body
8. Bleeder with Cap
Bleeder Torque N·m (kg·cm / lb·in)
8 (80 / 69)
7. Piston Seal
•Apply special rubber grease to the piston seal and
cylinder wall, then insert the piston seal into the
cylinder. The special rubber grease is included in
the repair kit.
INSPECTION AND REPAIR
Make necessary parts replacement, if wear, damage,
corrosion or any other abnormal conditions are found
through inspection.
Check the following parts;
•Rotor
•Cylinder body
•Cylinder bore
•Piston
•Guide bolt, Lock bolt
•Support bracket
NOTE:
The piston seal, boot ring and dust boot are to be
replaced each time the caliper is overhauled.
Discard these used rubber parts and replace with
new ones.
5. Piston