Abs; System Description - Triumph 2012 Tiger 800 Service Manual

Brakes

ABS

System Description

The ABS versions of the Tiger 800 and Tiger 800XC are
fitted with an electronic anti-lock brake system <ABS>
which is designed to prevent the wheels from locking or
skidding by reducing braking effort to the front or rear
brake caliper when wheel-lock is detected.
The system consists of a hydraulic modulator and ECM
assembly mou nted to a bracket to the rear of the airbox, a
front wheel speed sensor mounted to the front fork, and a
rear wheel speed sensor mounted to the rea r brake
caliper carrier.
Both front and rear wheels have a pulser ring mounted on
to the wheel, the front being mounted to the wheel hub,
the rear being mounted to the rear brake disc.
The front and rear master cylinders are connected via
lines to the modu lator and from the modulator the pipes
connect to the brake calipers. The calipers and master
cylinders are identical to
motorcycle.
The front and rea r brake circuits operate as separate
systems. The front and rear brakes are not connected in
any way inside the modulator.
The modulator ECM continuously calculates the front and
rear wheel speeds, and from these inputs the ECM
calculates the estimated
deceleration/acceleration, the wheel speed difference and
the wheel slip <skid) rate. This is calculated by comparing
the calculated wheel speeds with the calculated vehicle
speed, so that if one wheel speed deviates significantly
from the other two readings, this wheel is determined to
be skidding.
Under braking, if the modulator detects that either wheel
is about to slip, due to the brake force exceeding the
available traction between the tyre and road surface (the
wheel will beg in to slip or 'skid'), the ECM very rapidly
releases and re-appl ies the brake pressure to prevent the
wheel from skidding.
14.44
the non-ABS equipped
motorcycle speed, wheel
SeiVice Manual Tiger 800 and Tiger 800XC
-
This is felt through the brake pedal or lever as a ra pid
' pulsing'.
If the rider reduces braking effort, or traction increases <so
that traction exceeds braking force, the wheel will rotate
once more) the wheel will no longer lock up. The ABS
system will detect this and stop controlling brake pressure,
and return to its mon itoring state.
The system has a self diagnostic function built-in which
mon itors the fail safe relay, solenoid valves, motor relay,
wheel speed sensors, power supply and ground, as well as
internal ECM functions. In the event of a malfunction
being detected, the ECM will illuminate the ABS warning
lig ht, and store a diagnostic trouble code in the system
memory. This stored data can then be recovered using a
special service tool which is mandatory for all Triumph
dealers. I n this way, precise d iagnosis of a fault can be
made and the fault qu ickly rectified.
Under normal operation, the ABS warning light will flash
on and off after ignition on until the vehicle speed
exceeds 6 mph ( 1 0 km/h). If a trouble code is stored the
ABS warning light will stay illuminated and the ABS will
not function, however the brakes will operate normally. If
the ABS warn ing light does not extinguish, or illuminates
whilst the motorcycle is being ridden, refer . to the ABS
system diagnostics <see page
14-48).