2004 ISUZU TF SERIES change wheel

4C1-36 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”.

BRAKE CONTROL SYSTEM 5A-19

System Components
Electronic Hydraulic Control Unit (EHCU), four Wheel
Speed Sensors, two Warning 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 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: When failure occurs in ABS.
The power supply to solenoid Valve is cut.

ABS Warning Lamp


825L300001
Vehicles equipped with the Anti-lock Brake System
have an amber “ABS” warning lamp in 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
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
to the “ON” position.
If the “ABS” warning lamp stays “ON” after the ignition
switch is 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
diagnosis 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 4WD 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
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 features is being used.
When 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.

5A-20 BRAKE CONTROL SYSTEM

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 a slip of a rear wheel
becomes large more than fixed compared with a front
wheel about the rate of a slip in order to perform
braking force distribution of a front wheel and a rear
wheel, the brake fluid pressure of a rear wheel will be
controlled. EBD enables it to always utilize the braking
power of a rear wheel for the maximum according to
the load change concerning the back axis by vehicles
loading states (No luggage, loading, etc.), deceleration,
etc. Brake fluid pressure control to a rear wheel is
performed by the EBD function which used 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
Revolution per Second
VDC
DC Volts
VAC
AC Volts
W/L
Warning Lamp
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 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 FLOWCHART” 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 Tool
Some diagnosis procedures in this section require the
installation of a special tool.

5-8840-0366-0 High Impedance Multimeter
When circuit measurements are requested, use a
circuit tester with high impedance.

5A-26 BRAKE CONTROL SYSTEM

DATA LIST (Tech 2)
The data displayed by DATA LIST are as follows:


Strings Units Description 2WD 4WD
Front Left Wheel Speed km/h (MPH)
Front Right Wheel Speed km/h (MPH)
Rear Left Wheel Speed km/h (MPH)
Rear Right Wheel Speed km/h (MPH) Start the vehicle and make sure of linear
change in each wheel speed
Brake Switch Open/Closed Brake switch is “closed” when brake pedal is
stepped on.
ABS Warning Lamp On/Off To be “Off” usually
EBD Warning Lamp On/Off To be “Off” usually
ABS Stop State On/Off To be “Off” usually
ABS Relay Active/Inactive To be “Active” usually
Return Pump Active/Inactive To be “Inactive” usually
DTC Status No DTC To be “No DTC” usually
4 Wheel Drive Status Yes/No To be “Yes” usually
-
FL Dump Valve Commanded
(Front Left) Active/Inactive
FL Isolation Valve Commanded
(Front Left) Active/Inactive
FR Dump Valve Commanded
(Front Right) Active/Inactive
FR Isolation Valve Commanded
(Front Right) Active/Inactive
Rear Dump Valve Commanded Active/Inactive
Rear Isolation Valve Commanded Active/Inactive
FL Dump Valve Feedback
(Front Left) Active/Inactive
FL Isolation Valve Feedback
(Front Left) Active/Inactive
FR Dump Valve Feedback
(Front Right) Active/Inactive
FR Isolation Valve Feedback
(Front Right) Active/Inactive
Rear Dump Valve Feedback Active/Inactive
Rear Isolation Valve Feedback Active/InactiveEach valve is “Active” when each valve is
opereted.
G-Sensor Output V 2.0~3.0V when vehicle speed is 0 km/h (flat
place) -
Battery Voltage V The voltage value currently supplied to EHCU
Diagnostics Connector Open/Closed Diagnostics connector is “Open” when
diagnostics connector is connected.

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
2, (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
2, both have identical
ascending ratio.
However, because of the operation of spring
3 in the wheel
cylinder side, wheel cylinder fluid pressure operate to
preserve the balance against the master cylinder fluid
pressure on the lower level with the difference in pressure
resulting from this spring.
03260002-2


Valve Maintenance
In the case of fluid leak or other abnormalities, 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.

5C-22 BRAKES

RTW35CSH001001






Operation
1) Outline
When 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.

RTW35CSH001101

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).

RTW35CSH001201

3) Cutting point.
The cutting point is given by relation between force (F), tha
t
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 outle
t
pressure (B). The bypass piston (2) continues on the res
t
position by equilibrium of (A) and (C) pressure.

ELECTRICAL-BODY AND CHASSIS 8A-153

HEADLIGHT LEVELING SWITCH
Incorrect beam angle due to load change can be corrected.
A four position switch, 0-3, can alter the beam angle through
1.7 degrees on the long wheel base model and 2.17 degrees
on the short wheel base model.
825R300049

Inspection
Check to see if there is any continuity between the terminals of
the leveling switch.
Replace the switch when the result of inspection is found
abnormal.



Removal
Preparation:
Disconnect the battery ground cable.
1. Ventilation grille
2. Harness connector
3. Headlight leveling switch
To remove the switch, push the lock from the back side of
the cluster assembly.



Installation
To install, follow the removal steps in the reverse noting the
following point.
1. Push in the switch with your fingers until it locks securely.

6C – 10 FUEL SYSTEM
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 dus
t
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: When 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: When 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 agains
t
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.