Purpose and Function
The anti-lock brake system is an additional active vehicle safety element. The advantages are:
- Stability while braking.
- Steerability while braking, evasive manoeuvres possible while braking.
- Optimal braking distance.
The electronic ABS, used for the first time in the Frontera, is a new system.
The use of a microprocessor in the ABS system enables self-diagnosis and thus makes diagnosis with TECH 1 possible.
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1 Hydraulic control unit
2 Brake master cylinder
3 Brake servo
4 Rear wheel speed sensors
5 Diagnostic plug
6 Coil integrated module
7 Front wheel speed sensor
8 ABS control indicator
The ABS is an addition to the conventional brake system (add-on system).
As long as there is no danger of wheel lock, the ABS remains passive, i.e. the brake pressure to the wheel cylinders corresponds to the pressure exerted by the driver. The pressure increase during normal braking is not influenced by the ABS control unit.
If a wheel tends to lock, the ABS decreases the pressure at the brake on the relevant wheel by draining off part of the brake fluid from the brake caliper into low pressure accumulators in the hydraulic control unit.
ABS regulation occurs in millisecond pulses during the complete braking process. This activity is signalled to the driver by:
- Brake pedal pulsing.
- Sound of ABS activity.
The pulsing in the brake pedal with slight brake pedal travel oscillations is caused by the brake fluid being pumped between the master cylinder and the hydraulic control unit.