Medium Duty Operator's Manual - Peterbilt Motors Company

USING THE BRAKE SYSTEM
sion. You could get hung up in NEUTRAL and lose the
benefit of engine braking. “Coasting” is illegal, and
also VERY dangerous.
Anti-Lock Braking System
This vehicle is equipped with an Anti-Lock Braking System
(ABS). ABS reduces the likelihood of a wheel locking.
If a wheel is about to lock during braking, the ABS will
automatically adjust hydraulic pressure to the brake calipers
on the appropriate wheel(s) to prevent wheel lock-up.
The ABS is automatically activated when the ignition
switch is turned on.
CAUTION: The center pin of the 7-way trailer
light line may be constantly powered for ABS.
Make sure it will not accidently turn on trailer
equipment.
ABS Warning Lamp
The ABS warning lamp will come on briefly, then go off,
when the key switch is first turned on. If the lamp remains
ON until a speed of 4 mph (6 km/h) is reached, then goes
STARTING AND OPERATING THE VEHICLE
OFF, there may be a stored fault code. If the lamp
remains ON when a speed in excess of 4 mph (6 km/h) is
reached, there may be an active fault in the ABS system.
CAUTION: If the ABS warning light does not
illuminate when the ignition is first turned on,
there is a problem with the bulb or wiring. You
should have this checked as soon as possible.
WARNING! No indication will be given via the
dashboard warning lights or buzzer if tires of
the wrong size are installed on your vehicle.
The Anti-Lock Brake System (ABS) is calibrated
for the specific tire revolutions per
mile. Use of a tire and/or wheel size different
from that originally installed on your vehicle
may cause the ABS system to not function
during a hard braking event. This could cause
an accident or serious personal injury. Consult
with your Peterbilt dealer before using a
different tire and/or wheel size than was originally
installed on your vehicle.
– 122 – Y53-6008A Medium Duty (R05/09)