CAT: 8612 November 2019 Page 235
PREVENTIVE MAINTENANCE
ANTI-LOCK BRAKING SYSTEM (ABS)
Below are some general notes on your Kenworth anti-lock braking system.
For detailed service information see the Kenworth Maintenance Manual. All
service work should be performed by a qualied technician at an authorised
service centre. The foundation brake system must be in proper working
order to ensure the best ABS performance.
Before welding anywhere on the vehicle detach the ABS Electronic Control
Unit (ECU) connector and all other electronic control units. Never detach
the ECU connector with the ignition turned ON.
ABS FAULT CODES
For fault codes related to the ABS system refer to Bendix publications
BW2428 or SD-13-4983 ‘EC-80 ABS/ATC Controllers’ (system specic)
under Air System section on your Electronic Customised Maintenance
Manual Section 4 - Braking, in the Driver Information Pack.
Check ABS wiring harnesses and piping periodically for chang or other
problems. No regular maintenance is required on the ABS components.
During wheel balancing, dyno testing, or any time the ignition is ON with
part of the ABS disconnected, a failure code will be recorded. Consult your
authorised Kenworth dealer for information on clearing the failure code.
If one wheel on any driven axle continues to slip or spin for approximately
4 seconds, this will cause the anti-lock controller for that axle to go into the
fail-safe mode, and the warning light will give a shutdown signal.
In this case the anti-lock system can be turned back on, and the warning
light extinguished by turning the key switch OFF and ON, after the vehicle
has been brought to a full stop. When the key switch is turned back on,
the warning light will illuminate and remain on for 3 to 5 seconds. This is a
built-in function test of the warning light.
If, due to operating conditions, a brake application causes either wheel on
the same axle to begin skidding, wheel speed sensors immediately signal
the anti-lock controller in the modulator assembly. The controller responds
instantly by signaling the solenoids in the modulator, which activate the air
valves, reducing application pressure as needed to prevent the wheels from
locking up. If this over-riding correction is eective, application pressure is
allowed to build up to the original input.
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