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Anti-lock Braking System(ABS)
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In normal conditions when the ignition is switched
on the ABS and EBD lamp will come on and then
switch off after 1 - 2 seconds. During this period
the system will perform self diagnosis is to confirm
that all inputs and outputs are working correctly.
If the ABS warning lamp remains on after this time
it means either:
1. The ABS system has not been connected or
the connector is loose.
2. The system has detected a failure and will
need to be diagnosed.
3. Battery or Ignition line fuses have blown out.
4. Ignition line is cut.
The EBD lamp is shared with the brake fluid level
and parking brake, hence if the EBD warning lamp
remains on after this time it means either:
1. The park brake is applied.
2. The Brake fluid level is low.
3. The ABS system has not been connected. or
the connector is loose.
4. Park brake switch/ harness of parking brake
or brake fluid is loose
5. The system has detected a failure and will
need to be diagnosed.
If the warning light does not come on during
Ignition, the fault should be sought in the
Instrument Cluster.
If the ABS system detects any fault that may
adversely affect its performance it will switch to a
fail safe shut down mode. When this happens
the electricity supply to the solenoid valves is
deactivated, stopping control signal output, this
causes the valves to switch to their default state.
(Open for inlet valves / Closed for Outlet valves)
In this condition, the conventional hydraulic brake
circuit will still function, allowing brake pressure to
reach all wheels. It should be noted that with an
ABS fault it will be possible to lock the wheels and
in the Case of an EBD failure the brake force
proportioning between front and rear will no longer
function and hence rear wheel lock is possible
before front wheel lock.