4C1-32 FRONT WHEEL DRIVE
(5)
After the ZERO setting is obtained, rotate the gaging arbor
until the dial indicator rod does not touch the gaging plate.
Record the number the dial indicator needle points to.
(6) Record the pinion depth code on the head of the drive
pinion.
The number indicates a necessary change in the pinion mounting distance. A plus number indicates the need for a
greater mounting distance (which can be achieved b
y
decreasing the shim thickness). A minus number indicates
the need for a smaller mounting distance (which can be
achieved by increasing the shim thickness). If examination
reveals pinion depth code “0”, the pinion is “nominal”.
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ISUZU KB P190 2007
5A-22 BRAKE CONTROL SYSTEM
System Components
Electronic Hydraulic Control Unit (EHCU), four W heel
Speed Sensors, two W arning Lamps, and G sensor.
Electronic Hydraulic Control Unit (EHCU)
The EHCU consists of ABS control circuits, fault
detector, and a fail-safe. It drives the EHCU according
to the signal from each sensor, cancelling ABS to return
to normal braking when a malfunction has occurred in
the ABS.
The EHCU has a self-diagnosing function which can
indicate faulty circuits during diagnosis.
The EHCU is mounted on the engine compartment rear
left side. It consists of a motor, solenoid valves and a
fail safe relay.
Solenoid Valves: Reduces or holds the caliper fluid
pressure for each front brake or both rear brakes
according to the signal sent from the EHCU.
Buffer chamber: Temporarily holds the brake fluid that
returns from the front and rear brake so that pressure of
front brake can be reduced smoothly.
Motor: Drives the pump according to the signal from
EHCU.
Fail safe Relay: W hen failure occurs in ABS.
The power supply to solenoid Valve is cut.
ABS Warning Lamp
RTW 75ASH000101
Vehicles equipped with the Anti-lock Brake System
have an amber “ABS” warning lamp on the instrument
panel. The “ABS” warning lamp will illuminate if a
malfunction in the Anti-lock Brake System is detected
by the Electronic Hydraulic Control Unit (EHCU). In the
case of an electronic malfunction, the EHCU will turn
“ON” the “ABS” warning lamp and disable the anti-lock
braking function.
The “ABS” warning lamp will turn “ON” for
approximately three seconds after the ignition switch is
in the “ON” position.
If the “ABS” warning lamp stays “ON” after the ignition
switch is in the “ON” position, or comes “ON” and stays
“ON” while driving, the Anti-lock Brake System should
be inspected for a malfunction according to the
diagnostic procedure.
Wheel Speed Sensor (WSS)
It consists of a sensor and a rotor. The sensor is
attached to the knuckle on the front wheels and to the
rear wheels.
The rotor is press-fit in the axle shaft.
G Sensor
The G sensor detects the vehicle deceleration speed
and sends a signal to the EHCU. In 4W D operation, all
four wheels may be decelerated in almost the same
phase, since all wheels are connected mechanically.
This tendency is noticeable, particularly on roads with
low friction coefficient, and the ABS control is adversely
affected.
The G sensor judges whether the friction coefficient of
the road surface is low or high, and changes the
EHCU's operating system to ensure ABS and EBD
control.
Normal and Anti-lock Braking
Under normal driving conditions, the Anti-lock Brake
System functions the same as a standard power
assisted brake system. However, with the detection of
wheel lock-up, a slight bump or kick-back will be felt in
the brake pedal. This pedal “bump” will be followed by a
series of short pedal pulsations which occurs in rapid
succession. The brake pedal pulsation will continue
until there is no longer a need for the anti-lock function
or until the vehicle is stopped. A slight ticking or popping
noise may be heard during brake applications when the
anti-lock feature is being used.
W hen the anti-lock feature is being used, the brake
pedal may rise even as the brakes are being applied.
This is also normal. Maintaining a constant force on the
pedal will provide the shortest stopping distance.
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ISUZU KB P190 2007
BRAKE CONTROL SYSTEM 5A-23
Electronic Brake-force Distribution (EBD) System
ABS has the EBD function. EBD is a function which
controls braking force distribution of a front wheel and a
rear wheel, and makes brake fluid pressure of a rear
wheel the optimal. If the rate of slip of a rear wheel
becomes greater compared to a front wheel, the brake
fluid pressure of a rear wheel will be controlled in order
to perform braking force distribution between the front
and rear wheels. EBD enables the braking power of a
rear wheel to always be utilized for the maximum
according to the load change concerning the back axis
according to the vehicle’s loading state (No luggage,
loading, etc.), deceleration, etc. Brake fluid pressure
control to a rear wheel is performed by the EBD function
which uses the ABS function without the mechanical
proportioning valve.
C05L300016
Brake Pedal Travel
Vehicles equipped with the Anti-lock Brake System may
be stopped by applying normal force to the brake pedal.
Although there is no need to push the pedal beyond the
point where it stops or holds the vehicle, by applying
more force the pedal will continue to travel toward the
floor.
This extra brake pedal travel is normal.
Acronyms and Abbreviations
Several acronyms and abbreviations are commonly
used throughout this section:
ABS
Anti-lock Brake System
CKT
Circuit
DLC
Data Link Connector
EBD
Electronic Brake-force Distribution
EHCU
Electronic Hydraulic Control Unit
FL
Front Left
FR
Front Right
GEN
Generator
H/U
Hydraulic Unit
MV
Millivolts
RR
Rear
RPS
Revolutions per Second
VDC
DC Volts
VAC
AC Volts
W/L
W arning Lamp
WSS
W heel Speed Sensor
General Diagnosis
General Information
ABS problems can be classified into two types, those
which can be detected by the ABS warning lamp and
those which can be detected as a vehicle abnormality
by the driver.
In either case, locate the fault in accordance with the
“BASIC DIAGNOSTIC FLOW CHART” 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 W rench
• Brake Fluid
• Special Tool
Some diagnosis procedures in this section require the
installation of a special tool.
5-8840-0366-0 High Impedance Multimeter
W hen circuit measurements are requested, use a circuit
tester with high impedance.
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ISUZU KB P190 2007
5A-32 BRAKE CONTROL SYSTEM
Data List (Tech 2)
The data displayed by DATA LIST are as follows:
Strings Units Description
FL W heel Speed (Front Left) Km/h (MPH)
FR W heel Speed (Front Right) Km/h (MPH)
RL W heel Speed (Rear Left) Km/h (MPH)
RR W heel Speed (Rear Right) Km/h (MPH) Start the vehicle and make sure of linear
change in each wheel speed.
Brake Switch On/Off Brake switch is “On” when brake pedal is stepped
on.
4 W heel Drive Status 2 W heel Drive/
4 W heel Drive
ABS W arning lamp
On/Off To be “Off” usually
EBD W arning Lamp On/Off To be “Off” usually
ABS State On/Off To be “Off” usually
Valve Relay Command Active/Inactive To be “Active” usually
Return Pump Relay Command Active/Inactive To be “Inactive” usually
EBD State
DTC Status No DTC/
DTCs Set To be “No DTC” usually
FL Release Solenoid Commanded
(Front Left) Active/Inactive
FL Hold Solenoid Commanded (Front
Left) Active/Inactive
FR Release Solenoid Commanded
(Front Right) Active/Inactive
FR Hold Solenoid Commanded (Front
Right) Active/Inactive
Rear Release Solenoid Valve
Commanded Active/Inactive
Rear Hold Solenoid Valve Commanded Active/Inactive
FL Release Solenoid Feedback (Front
Left) Active/Inactive
FL Hold Solenoid Feedback (Front Left) Active/Inactive
FR Release Solenoid Feedback (Front
Left) Active/Inactive
FR Hold Solenoid Feedback (Front Left) Active/Inactive
Rear Release Solenoid Feedback Active/Inactive
Rear Hold Solenoid Valve Feedback Active/Inactive Each valve is “Active” when each valve is operated.
Deceleration Sensor
V 2.0~3.0V when vehicle speed is 0km/h (flat place)
Battery Voltage V The voltage value currently supplied to EHCU
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ISUZU KB P190 2007
5C-20 BRAKES
•
••
•
Operation
The operation of the P-valve by the master cylinde
r
pressure is unchanged up to the brake points
A and B.
If master cylinder fluid pressure penetrates into the second break point
B, the fluid pressure pressing against the seal
, (which isolated route 4 and route 5), passing the route
4of the master cylinder side, overcomes the operating
force of the spring
3 + fluid pressure affecting the seal 2of
the wheel cylinder, and presses the piston
1to the right
side, resulting in the opening of the routes
4 and 5, and
canceling of the P-valve operation.
Then, because the master cylinder fluid pressure and the wheel cylinder fluid pressure, up to the point
C, operate on
the identical surface of the seal
, both have identical
ascending ratios.
However, because of the operation of spring
3in the wheel
cylinder side, wheel cylinder fluid pressure operates to
preserve the balance against the master cylinder fluid
pressure on the lower level with the difference in pressure
resulting from this spring.
RTW 75CSH001601
Valve Maintenance
In the case of a fluid leak or other abnormality, the faulty valve
should be replaced.
The valve is set up at the engine room.
Note:
The blend proportioning valve is not repairable and must
be replaced as a complete assembly.
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5C-22 BRAKES
RTW 35CSH001001
•
••
•
Operation
1) Outline
W hen the LSPV (Load Sensing Proportioning Valve) detects a change in load weight, the load sensing spring
stretches.
Its reaction force is transmitted to the bottom of the load sensing valve to secure an optimum rear wheel cylinde
r
fluid pressure break point in proportion to the actual load
weight.
Besides, if the front brake system should fail, the device is designed to prevent the master cylinder fluid pressure from
decreasing and to apply it directly to the rear wheel cylinde
r
to obtain a sufficient braking performance.
RTW 35CSH001101
2) Bellow cutting point.
The Force (F) keeps the main piston (1) the rest position. The inlet pressure (A) and outlet pressure (B) are the same
as well as the inlet pressure (C) from front master cylinder.
The bypass piston (2) is kept on rest position by equilibrium
of the pressures (A) and (C) and the bypass spring load (3).
RTW 35CSH001201
3) Cutting point.
The cutting point is given by relation between force (F), that is the load applied by suspension of the vehicle and the
main piston area (1). The cutting point is achieved when the
force generated by hydraulic pressure is upper than the
force (F) given by the load suspension. The main piston (1)
moves from the rest position closing the valve. In this
moment the inlet pressure (A) is upper than the outlet
pressure (B). The bypass piston (2) continues on the rest
position by equilibrium of (A) and (C) pressure.
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ISUZU KB P190 2007
FUEL SYSTEM 6C – 9
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system for
loose connection or leakage. For the fuel system
diagnosis, see Section “Driveability and Emission".
1. Disconnect battery ground cable.
2. Loosen slowly the fuel filler cap.
NOTE: Be careful not to spouting out fuel because of change
the pressure in the fuel tank.
NOTE: Cover opening of the filler neck to prevent any dust
entering.
3. Jack up the vehicle.
4. Support underneath of the fuel tank with a lifter.
5. Remove the inner liner of the wheel house at rear left side.
6. Remove fixing bolt of the filler neck from the body.
7. Disconnect the quick connector (3) of the fuel tube from the
fuel pipe.
NOTE: Cover the quick connector to prevent any dust entering
and fuel leakage.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in this
section when performing any repairs.
8. Remove fixing bolt (1) of the tank band and remove the tank band (2).
9. Disconnect the pump and sender connector on the fuel
pump and remove the harness from weld clip on the fuel
tank.
10. Lower the fuel tank (5).
NOTE: W hen lower the fuel tank from the vehicle, don’t scratch
each hose and tube by around other parts.
Installation
1. Raise the fuel tank.
NOTE: W hen raise the fuel tank to the vehicle, don’t scratch
each hose and tube by around other parts.
2. Connect the pump and sender connector to the fuel pump and install the harness to weld clip on the tank.
NOTE: The connector must be certainly connected against
stopper.
3. Install the tank band and fasten bolt.
Torque N·m (kg·m / lb ft)
68 (6.9 / 50)
NOTE: The anchor of the tank band must be certainly installed
to guide hole on frame.
4. Connect the quick connector of the fuel tube to the fuel pipe and the evapo tube from evapo joint connector.
NOTE: Pull off the left checker on the fuel pipe.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in this
section when performing any repairs.
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6E-262 Engine Control System (4JH1)
Checks Action
Additional Checks •
Electromagnetic interference (EMI) on the reference circuit can cause an engine miss
condition. The scan tool can usually detect EMI by monitoring the engine speed. A
sudden increase in speed with little change in actual engine speed change indicates that
EMI is present. If a problem exists, check routing of high voltage components, such as
fuel injection solenoid valve wiring, near the sensor circuits.
• Inspect for faulty engine mounts.
• Inspect faulty crank pulley.
• Inspect faulty generator & A/C compressor.
• Inspect the generator output voltage. Repair if less than 9 volts or more than 16 volts.
• Inspect the EGR system operating correctly.
• Inspect the A/C operation.
Cut Out, Misses
Checks Action
DEFINITION:A constant jerking that follows the engine speed, usually more pronounced as the engine load increase. The
exhaust has a steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to
cut-out.
Preliminary Check • Diagnostic System Check - Engine Controls.
• Inspect that the harness connectors are correctly connected.
• Inspect the engine control module (ECM) and fuel injection pump control unit (PCU)
grounds for being clean, tight, and in their proper locations.
• Inspect the scan tool Data List in this section.
• Inspect the Service Bulletins for ECM software updates.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the scan tool
Data List in this section.
• Use the scan tool to observe the Accelerator Pedal Position. Accelerator Pedal
Position indicating angle parameter should change linearly from 0% to 100%
according to the accelerator pedal operation.
• Inspect the crankshaft position (CKP) sensor is tight and the flywheel circumference
is not damaged.
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ISUZU KB P190 2007