Below is a reprint of ABS
information courtesy of the PT Cruiser Club. This content is copyrighted
by PT Cruiser Club.
Information we thought you
would like about
Anti-lock Brakes: PT Cruiser ABS explained
1) What is ABS (Anti-lock Brakes)?
2) How do I tell if my PT Cruiser has
ABS?
3) What happens during an ABS stop,
what does the driver feel?
4) I'm going down a hill that is a
sheet of ice, when I apply the brakes what
should I see, feel, hear from my ABS?
5) What is Low-Speed Traction
Control?
6) Will Low-Speed Traction Control
have any effect on my mileage?
7) Do all 4 tire sizes have to be the
same height front to rear if you have ABS?
1) What is ABS
(Anti-lock Brakes)?
The PT Cruiser can be ordered with
the optional Teves Mark 20 Antilock Brake System with Low-speed Traction
Control. The purpose of the antilock brake system is to prevent wheel
lockup under braking conditions on virtually any type of road surface.
Antilock braking is desirable because a vehicle that is stopped without
locking the wheels retains directional stability and some steering
capability. This allows the driver to retain greater control of the
vehicle during braking. It is important to remember that the antilock
brake system does not shorten the vehicle stopping distance under all
driving conditions, but provides improved control of the vehicle while
stopping. Vehicle stopping distance is still dependent on vehicle speed,
weight, tires, road surface, and other factors.
The PT Cruiser ABS system is more
than just anti-lock brakes. The PT Cruiser comes standard with front
disc/rear drum brakes. The 4-wheel anti-lock brakes with Low-speed
Traction Control is a $595 option for all models and includes 4 wheel disc
brakes.
2) How do I tell if my PT Cruiser has ABS?
If your PT Cruiser has ABS, it
will have these unique features: Rear disc brakes (instead of drum
brakes), a "TRAC OFF" switch below the radio to the left of the
power outlet, and at "key-on" you will see the ABS lamp
illuminate momentarily in the lower right corner of the tachometer.
3) What happens during an ABS stop, what does the driver
feel?
ABS is automatically activated
when needed. NOTE: Pumping of the brake pedal will diminish the
effectiveness of Anti-lock brakes and may lead to an accident. Pumping
makes the stopping distance longer. Just press firmly on your brake pedal
when you need to slow down or stop.
When stopping conditions activate
the antilock brakes, the driver may feel some normal vibrations/
pulsations in the brake pedal and may hear the electric solenoid valves
clicking and the pump motor running. The vibrations/pulsations are caused
by the isolating, building and decaying of brake fluid pressure within the
brake lines. The ABS system prevents complete wheel lock-up, but some
wheel slip is required for the best braking performance. This slip may
result in some tire chirping, depending on the road surface. The chirping
sound should not be interpreted as total wheel lock-up, which leaves black
tire marks on dry pavement; antilock braking may leave some light marks. At
the end of an ABS stop, the ABS may function all the way down to near 0
km/h (0 mph). There may be a slight brake pedal drop anytime the ABS is
deactivated.
In case of braking on a bumpy
surface, the ABS system may detect wheel locking tendencies due to wheel
hop and cycle ABS. In the scenario the brake pedal may pulsate with a
perceived loss of declaration. ABS braking may also be activated at times
while on dry pavement with sand, gravel, or other loose debris on the
road.
4) I'm going down a hill that is a sheet of ice, when I
apply the brakes what should I see, feel, hear from my ABS?
The driver may feel some normal
vibrations/pulsations in the brake pedal.
NOTE: There needs to be some
degree of traction available for a vehicle to stop, even if your vehicle
is equipped with ABS, you still need to be cautious of icy, snowy roads.
Traction devices and winter driving precautions may still be necessary.
Lower your speeds, increase following distances and use snow tires if
necessary (see owners manual). Under some winter conditions it may be
advisable not to drive until conditions improve. Even when equipped with
ABS, you will need greater stopping distance on icy, snowy, slippery
roads.
5) What is Low-Speed Traction Control?
If you accelerate in any kind of
slippery conditions; snow, ice, rain, mud, and the wheels spin (loose
grip), the wheel speed sensors notice the loose spin by comparing wheel
rotation speed with the other wheels that have grip. After wheel spin and
loss of grip are detected, the ABS valves are modulated (rapid brake
cycling) in the proper amount on the wheel slipping so as to not stop the
car but to regain grip while still accelerating. When this occurs, the
TRAC indicator light located above the instrument cluster odometer will
flash. The LSTC system functions only at speeds below 35 MPH (56 km/h)
Do you recommend leaving the
"TRAC OFF" switch on or off for normal driving?
Leave it on, the only time you
would need to turn "TRAC OFF" is if you are stuck in mud, ice or
snow and need to "rock" the vehicle.
6) Will Low-Speed Traction Control have any effect on my
mileage?
No, it is a passive system that
only activates briefly when needed.
7) Do all 4 tire sizes have to be the same height front to
rear if you have ABS?
Yes, the ABS is controlled by
software that monitors each wheel sensor for calculating each wheels
revolutions per second. If you add wheels that are not the same diameter
in front and rear, the wheels may spin at different rates and the computer
may think there is a wheel slippage or mismatch and the ABS trouble lamp
will come on. However, the system will compensate when the compact spare
is used.
Note: always follow all traffic
laws and obey the speed limit. Please refer to the owners manual/service
manual for service information and safety precautions, this information is
not intended as substitute for the service manual/owners manual. This
information is subject to revision or change. PTCC accepts no
responsibility for any accidents, damage or injury.
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