Main control
The ABS control unit determines the wheel speed from the wheel sensor signal it receives, then calculates the vehicle speed based on the determined wheel speeds. The control unit determines the vehicle speed during deceleration by subtracting the corresponding values from the vehicle speed before deceleration.
The ABS control unit calculates the relative slip for each wheel and transmits a control signal to the electromagnetic modulator assembly when the relative slip is too high. The pressure reduction circuit is a system of three control channels for each front and both rear wheels. Pressure reduction control is a system of three modes such as pressure reduction, pressure containment and pressure enhancement. The wheel sensor signal is a system of four channels from each wheel.
Self-diagnosis function
The ABS control unit is equipped with a chronometer control.
The ABS control unit is equipped with a main CPU (processor unit) and auxiliary CPU, both CPUs control each other.
Both CPUs control the electrical circuit of the system. When at least one of the CPUs detects a fault, both switch the system to system failure mode or deceleration control mode,
Self-diagnosis can be classified into four categories as follows.
1. Initial diagnosis
2. Out of ABS control
3. During ABS control
4. During a warning
On-board diagnostic functions
The ABS control unit is equipped with a data connector.
The ABS system can be diagnosed by the HONDA PGM-H tester.
ABS modulator
The ABS modulator consists of an input solenoid valve, an output solenoid valve, a filler tank, a pump, a pump motor and a vibration damping chamber. The ABS unit with forward pressure reduction control, which directly reduces the brake fluid pressure, is entirely included in the modulator, it is also known as the recirculation type because the brake fluid circulates through the brake fluid reservoir and master cylinder.
The hydraulic control has three modes: pressure reduction, pressure holding and pressure increasing.
The hydraulic circuit consists of four independent channels for each wheel
Pressure boost mode:
- The inlet valve is open, the outlet valve is closed. The master cylinder fluid is pumped out of the brake cylinders.
Pressure holding mode:
- The inlet valve is closed, the outlet valve is closed.
- The brake cylinder fluid is shut off by the inlet and outlet valves.
Pressure reduction mode:
- The inlet valve is closed, the outlet valve is open.
- Brake fluid flows through the outlet valve to the reservoir reservoir.
Engine operating mode:
- When the pressure reduction mode is turned on, the pump motor turns on.
- When ABS stops operating, the pump motor turns off.
- The filler tank fluid is pumped out by a pump and flows through the vibration damping chamber to the master brake cylinder.