four wheel drive GREAT WALL FLORID 2008 Service Manual

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Vehicle road test methods
1. Drive the vehicle and find out if the swaying is coming from the front tires or the back tires. Then replace the
identified problem tire with a good tire (one that has been tested on t\
he same model of vehicle).
2. If unable to determine the problem tire, replace the rear wheels. Continue with the road test. If the driving
condition obviously changes, replace the original tires, and only switch one at a time until the problem tire is
identified.
3. If no obvious improvement, replace all four tires with good tires, and then replace the original tires one by
one following the steps mentioned above.
Tire's abnormal wear and tear
Tire's abnormal wear and tear includes uneven and excessive
w e a r o f t h e t i r e . T h e r e a r e m a n y c a u s e s f o r t h i s . F o r
example, improper tire pressure, tire rotation has not been
timely maintained, bad driving habits, abnormal front wheel
location, etc.
Change the tires when the below situations happen:
1. When the extents of wear and tear of the front and rear
tires are different.
2. When any of the tire's tread has uneven wear and tear.
3. When the extents of the wear and tear of the left and right
front tires are different.
4. When the extents of wear and tear of the left and right rear
wheels are different.
5. When the groove of the tire tread wear appears abnormal
and the tire's contact area starts to flatten.
Inspect the front wheel alignment when the following
situations occur:
1. When the extents of the wear and tear of the left and right
front tires are different.
2. When any of the tire's tread has uneven wear and tear.
3. When the tread pattern strip or pattern block of a front
tire's single side is badly worn.
[A]
[B]
[A]: Steering problems, air pressure not sufficient, or tire rotation has not been timely maintained. [B]: Abnormal front wheel alignment, tire or wheel structure is not the same.
Radial tire sway
Here the sway means the vehicle's front or rear part shakes
from side to side, together or individually. Tire sway is
caused by the steel wire belt inside the tire not being straight.
The sway is the most obvious when the vehicle runs at the
speed of 8-48 km/h.
Road tests can help finding malfunctioning tires. If the
malfunction is with the rear tires, then left and right shaking
or "swaying" would take place at the back of the vehicle.
Here the driver of the vehicle would feel as if someone were
pushing from one side of the vehicle.
If the malfunction is with the front tires, swaying would be
even more obvious. The metal plate in the front may seem
moving back and forth, and the driver feels as if he/she were
at the vehicle's center of rotation.
Wear marks
There are several tread wear marks (refer to location A in the
diagram shown on the left) inside of the tire's pattern groove.
These marks indicate that the tire has been worn to the point
of replacing.
Before the tire's usage limit, indicated by the remaining
pattern's depth, reaches 1.6 mm (and its main pattern groove
bottom protrudes to the same level), for your safety, please
replace the tire.
When serious eccentric wear leads to the partial protrusion
of the cord fabric level, or outside objects damage the tire to
a depth that reaches the cord fabric level or steel band level,
stop using the tire.
A

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The X431 scanner possesses a waveform function. Wheel speed signal error (wheel speed sensor failure)
only appears when intermittent problems occure, such as high speed. When in use, some signal errors may
occasionally appear. Continue observing the waveform to make sure there is nothing abnormal.When driving
the vehicle on a flat and straight road, all four wheels' speed sensor waveform are extremely similar. One can
compare the two front wheels' with the two rear wheels' signal wave at t\
he same time.
Mechanical causes:
Signal gear distortion, loosened hub bearings, smudges on the sensor surface, etc, all may lead to wheel speed
signal intermittency and inaccuracy. Failure examples:
As shown above, once the intermittent failures with the wheel's speed sensor signal are detected, the ABS
control unit records the sensor problems and lights up the warning lamp.\
4. Wheel speed sensor velocity failure (ECU detects an excessive difference between the two wheels'
speed sensor signals).
Possible causes are the gear's wheel speed sensor gap is overly large, or the wheel speed sensor signal is
experiencing interference. For this, first determine which sensor is emitting the signal, and then use failure
three's maintenance methods.
Areas of Importance
1. Sometimes, in order to determine whether there is a common brake system problem or an ABS
problem, the ABS must be terminated by pulling out its ABSECU connector or fuse. At this time the
ABS/EBD loses function as well. On muddy, icy, or snowy roads, the vehicle may fishtail or slide, in
which cases one must be extremely careful to avoid hard braking.
2. The ABS malfunction rate is extremely low, when the brake system shows any problem (before the
warning lamp goes on), first eliminate the normal brake system problems, then consider the ABS mal-
functions.
3. When raining or on gravel, this adjusting process is longer than the standard process, because this
kind of road's unstable adhesion coefficient will lead to a difference between the sliding measurement
and calculation procedures, thus it is necessary to remind drivers to be especially careful when driving
under the circumstances mentioned above.
4. ABSECU Areas of Importance:
(a) The ABSECU is easily damaged from impacts or collisions, thus pay attention to ensure the ECU avoids
such incidents.
(b) High temperature environments can also easily damage the ECU, so when the vehicle undergoes hot paint
work, make sure to first take the ECU out of the vehicle.
(c) When the power switch is ON, do not disassemble the system's electrical elements and wire harness plugs,
in order to avoid damage to the ECU. If removal or installation must be carried out, be sure to disconnect
the ignition switch firstly. When welding components or circuits to the system, the wire harness plug
V( Km/h)
60
30
Signal interrupt
t