ABS Control Unit

MAIN CONTROL
The ABS control unit detects the wheel speed based on the wheel sensor signal it received, then it calculates the vehicle speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration based on the rate of deceleration.

The ABS control unit calculates the slip rate of each wheel, and it transmits the control signal to the modulator unit solenoid valve when the slip rate is high.

The pressure reduction control has three-modes: pressure reduction, pressure retaining, and pressure intensifying.

Self-diagnosis Table:

Operation Mode Table:

SELF-DIAGNOSIS
1. The ABS control unit is equipped with a main CPU and a sub CPU, that check each other for problems.
2. The CPUs check the circuit of the system.
3. Self-diagnosis can be classified into two categories:
- Initial diagnosis: Performed right after the engine starts and until the ABS indicator goes off.
- Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.
4. When a problem is detected by self-diagnosis, the system:
- Turns the fail-safe relay OFF
- Turns the solenoid valve OFF
- Turn the pump motor OFF
- Turns the ABS indicator ON

ON-BOARD DIAGNOSIS FUNCTION
The ABS control unit is connected to the 16P Data Link Connector.
The ABS can be diagnosed with the Honda PGM Tester.
The ALB Checker cannot be used with this system. For air bleeding, and checking wheel sensor signals, use the Honda PGM Tester. See the Honda PGM Tester user's manuals for specific operating instructions.