Fiat 1998 Marea Weekend, Service Manual

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Marea - Marea Weekend
Braking system
Anti-lock brakes
33.
Pressure maintenance stage
P4F11BD01
1. Electronic control unit
2. Low pressure accumulator (reservoir)
3. Recovery pump motor
4. Recovery pump
5. Restricter
6. Brake pump
7. Brake servo
8. Multi-polar ring
9. Pressurizing solenoid valve
10. Discharging solenoid valve
11. Brake caliper
12. Rpm sensor
During this stage the electronic control unit (1) connects the pressurizing solenoid valve (9) to earth
which closes, whilst the discharing solenoid valve (10) is already closed as it is not connected to earth.
The hydraulic connection between the brake pump (6) and the brake caliper (11) in interrupted (wait-
ing position).
The pressure in the brake caliper (11) is kept constant at the value reached previously, even if the pres-
sure on the brake pedal is increased.
In spite of this the braking force maintains a constant slowing down action, the speed of the wheel
varies, according to the adhesion on the ground, until the rpm sensor (12) signal detects a value which
is comparable to the reference speed calculated by the electronic control unit (1).
At this point the control unit moves on from the pressure maintenance stage to the increase stage (if the
wheel is accelerating) or to the decrease stage (if the wheel tends to lock).
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