(ABS Braking Torque Control Circuit, Function - GF42.30-P-2000GG)
MODEL 463.### ## up to 127356 up to 31.8.01 with CODE (B02) ABS brake system
ABS four channel system
ABS three-channel system
ABS three-channel system in model 463.308/330/331
The corresponding functions are controlled in the ABS hydraulic unit with the components of the electrics/electrons.
The ABS control unit receives input signals from the following components:
- 4 RPM sensor
- Stop lamp switch
- Acceleration sensor (only four-channel system)
The input signals are processed in the ABS control unit into output signals for the following components:
- Solenoid valves
- Return flow pump (via relay)
- ABS indicator lamp (actuation direct, serial or via CAN data line)
Based on the input signals the ABS control unit decides which of the 4 operating modes
- Normal mode
- ABS control mode - build up pressure
- ABS control mode - hold pressure
- ABS control mode - reduce pressure
is to be activated.
Normal operation
In this case no rpm differences exist (which require a control mode).
All solenoid valves in the ABS hydraulic unit are de-energized in the basic position. The system is ready for braking.
This operating mode is also adjusted if a fault is present in the ABS.
ABS control mode
From the rpm signals present the ABS control unit detects that the preconditions for an ABS control exist.
The corresponding solenoid valves are actuated by the ABS circuits in the ABS control unit.
The solenoid valves of the left or right front axle are actuated separately in the ABS hydraulic unit (A7/3).
The solenoid valves for the rear axle act jointly on the two rear wheels for the ABS control process. If an ABS control is effective, then a rapid pressure change between the pressure buildup phase, pressure holding phase and pressure reduction phase takes place at the wheel brakes.
This ABS control process is noticeable by a pulsating brake pedal.
| ABS normal mode and pressure build up control function | GF42.30-P-3100GG | ||
| ABS hold pressure control function | GF42.30-P-3200GG | ||
| ABS pressure reduction control function | GF42.30-P-3300GG |