Chevrolet 4500 HD 2023 Manual page 181

180 Driving and Operating
Driving in sand or on a muddy road may
adversely affect the brakes and ABS sensors.
Wash the vehicle to remove sand and mud
after operating the vehicle in sandy or
muddy conditions.
Before washing the vehicle, provide
necessary protection to prevent water from
being splashed on the ABS components
(sensors and actuators). Especially when
using high-pressure washing, be careful not
to allow water to be directly sprayed onto
the ABS components and their harness
connectors.
These are not signs of ABS malfunction:
Soon after you start the engine and the
vehicle starts moving, the sound of motor
or valve working may be heard from the
rear of the vehicle or underside of the
cab. This sound is from a self-check by
the ABS system and is normal. In
addition, you may also feel some
vibration if the brake pedal is pressed at
this time.
When ABS is operating, vibration is felt
on the brake pedal and steering wheel
and you may hear the system operating.
This is normal when ABS is properly
operating.
The exhaust brake may release when ABS
is activated and the exhaust brake is in
operation.
ABS is more likely to be activated when
the brake is applied during cornering or
driving over a bump. This is because
inside wheels or wheels that have gone
over a bump tend to lock.
ABS is not activated immediately after
starting the vehicle. It is activated only
when the vehicle speed reaches approx.
10 km/h (6 MPH). ABS operation is
inactive when the vehicle speed reduces
to approx. 5 km/h (3 MPH).
ABS Operation Indications and Signs
ABS warning light
Operation Indications of ABS
When the engine control switch is placed
into the "ON" position, the ABS warning
light comes on and then goes out in approx.
3 seconds. The ABS is normal if the warning
light goes out.
Operation Signs of ABS
When ABS is activated, slight vibration is
generated on the brake pedal (hydraulic
brake model) and steering wheel, and an
operating sound can be heard from the ABS
equipment.
If the ABS warning light does any of the
following, the ABS may be faulty. Please
contact the nearest dealer.
If the ABS warning light comes on during
driving
The light does not come on when the
engine control switch is placed into the
"ON" position
See Antilock Brake System (ABS) Warning
Light 0 57.
Even if a problem has occurred with the
ABS, the regular brakes will still work
normally. However, ABS will not operate.
Precautions for Driving an ABS-Equipped
Vehicle
ABS is not a device that enables driving and
stopping under conditions exceeding safe
driving limits. Always drive safely.