Dodge Neon 2001 Service Manual page 40

PL
BRAKES-ABS
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 28
INSPECTION AND ROAD TEST . . . . . . . . . . . . 28
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 29
FRONT WHEEL SPEED SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
BRAKES-ABS
DESCRIPTION
This Service Manual Supplement includes
ONLY the information that is new or updated
for 2001 Model Year. All other Service Manual
information is in the 2000 Model Year Service
Manual.
When you are using this information you may
be referred to another section of the Service
Manual. The refer to is written differently than
in prior years.
OPERATION - ANTILOCK BRAKE SYSTEM
There are a few performance characteristics of the
Mark 20e Antilock Brake System that may at first
seem abnormal, but in fact are normal. These char-
acteristics are described below.
NORMAL BRAKING
Under normal braking conditions, the ABS func-
tions the same as a standard base brake system with
a diagonally split master cylinder and conventional
vacuum assist.
ABS BRAKING
ABS operation is available at all vehicle speeds
above 5–8 km/h (3–5 mph). If a wheel locking ten-
dency is detected during a brake application, the
brake system enters the ABS mode. During ABS
braking, hydraulic pressure in the four wheel circuits
is modulated to prevent any wheel from locking.
Each wheel circuit is designed with a set of electric
solenoids to allow modulation, although for vehicle
stability, both rear wheel solenoids receive the same
2001 NEON
BRAKES-ABS
TABLE OF CONTENTS
page
OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
REAR WHEEL SPEED SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
TONE WHEEL
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
electrical signal. Wheel lockup may be perceived at
the very end of an ABS stop and is considered nor-
mal.
During an ABS stop, the brakes hydraulic system
is still diagonally split. However, the brake system
pressure is further split into four control channels.
During antilock operation of the vehicle's brake sys-
tem, the wheels are controlled independently and are
on separate control channels.
The system can build, hold and release pressure at
each wheel, depending on signals generated by the
wheel speed sensors (WSS) at each wheel and
received at the controller antilock brake (CAB).
NOISE AND BRAKE PEDAL FEEL
During ABS braking, some brake pedal movement
may be felt. In addition, ABS braking will create
ticking, popping, or groaning noises heard by the
driver. This is normal and is due to pressurized fluid
being transferred between the master cylinder and
the brakes. If ABS operation occurs during hard
braking, some pulsation may be felt in the vehicle
body due to fore-and-aft movement of the suspension
as brake pressures are modulated.
At the end of an ABS stop, ABS is turned off when
the vehicle is slowed to a speed of 5–6 km/h (3–4
mph). There may be a slight brake pedal drop any-
time that the ABS is deactivated, such as at the end
of the stop when the vehicle speed is less than 5
km/h (3 mph) or during an ABS stop where ABS is
no longer required. These conditions exist when a
vehicle is being stopped on a road surface with
patches of ice, loose gravel, or sand on it. Also, stop-
ping a vehicle on a bumpy road surface activates
ABS because of the wheel hop caused by the bumps.
BRAKES-ABS 5s - 27
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