SECTION 5B - ABS & ABS/ETC
CAUTION:
This vehicle will be equipped with a Supplemental Restraint System (SRS). An SRS
will consist of either seat belt pre-tensioners and a driver's side air bag, or seat belt
pre-tensioners and a driver's and front passenger's side air bags. Refer to
CAUTIONS, Section 12M, before performing any service operation on or around any
SRS components, the steering mechanism or wiring. Failure to follow the CAUTIONS
could result in SRS deployment, resu lting in possible perso nal in jury or u nnecessary
SRS system repairs.
CAUTION:
This vehicle may be equipped with LPG (Liquefied Petroleum Gas). In the interests of
safety, the LPG fuel system should be isolated by turning ‘OFF’ the manual service
valve and then draining the L PG service lines, before any service w ork is carried out
on the vehicle. Refer to the LPG leaflet included with the Owner's Handbook for
details or LPG Section 2 for more specific servicing information.
CAUTION:
Whenever any component that forms part of the ABS or ABS/ETC (if fitted), is
disturbed during Service Operations, it is vital that the complete ABS or ABS/ETC
system is checked, using the procedure as detailed in 4. DIAGNOSIS, ABS or
ABS/ETC FUNCTION CHECK, in Section 12L ABS & ABS/ETC.
1. GENERAL DESCRIPTI ON
The Anti-Lock Braking System (ABS), is fitted as standard equipment on VT Series Berlina and Calais vehicles as
well as SS and Acclaim models.
When the foot brake is applied, the change in road wheel rotational speed is monitored by magnetic impulse
sensors at the front wheels and inductive wheel-speed sensors at the rear, that provide the necessary signals to the
ABS Control Module.
The conventional portion of this braking system (non ABS), comprises the standard, service braking system but with
specific brake pipe lines and harness. The master cylinder can be externally identified by the fact that there are two
brake lines connected to it, rather than three, as with the standard braking system.
The front wheel hubs incorporate the wheel speed sensors for that location, while the rear wheel speed sensors
have toothed pulse rings attached to each of the inner axle flanges.
If a drop in wheel speed is detected by a wheel sensor under braking and the generated signal is outside pre-set
parameters, the ABS Control Module will regulate the hydraulic pressure to that wheel, to prevent wheel lock-up
with subsequent braking efficiency loss. Apart from this action, the braking system operates exactly the same as the
conventional system.
Refer to Section 12L ABS & ABS/ETC, for a complete overview of this system, including general information,
general description and principles of operation.
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2. SERVICE INFORMATION
For servicing details on the ABS and ABS/ETC, reference can be made to the following Sections:
a. Section 3 FRONT SUSPENSION, for information relating to front wheel bearing/hub/sensor removal and/or
installation operations.
b. Section 4B2 FINAL DRIVE AND DRIVE SHAFTS, for details of rear, inner axle sensor removal and
adjustment details.
c. General brake bleeding operations for the ABS and ABS/ETC are the same as for the standard, foundation
braking system. This operation is described in Section 5A STANDARD BRAKES.
IMPORTANT:
When bleeding operations are carried out, that involve the ABS hydraulic Control Module, then specific
procedures must be followed that require the use of TECH 2. Re fer to Section 12L ABS & ABS/ETC.
d. Refer to Section 12L ABS & ABS/ETC for electronic and other hydraulic operations not described above.
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