ABS Control Unit Inputs and Outputs

ABS Control Unit Inputs and Outputs





Part 1 of 2





Part 2 of 2
ABS Control Unit Inputs and Outputs for Connector A (22P)




ABS Control Unit Inputs and Outputs for Connector B (12P)

Features
When the brake pedal is pressed during driving, the wheels can lock before the vehicle comes to a stop. In such an event, the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of the vehicle is reduced if the rear wheels are locked, creating an extremely unstable condition. The ABS precisely controls the slip rate of the wheels to ensure maximum grip force from the tires, and it thereby ensures maneuverability and stability of the vehicle.





The ABS calculates the slip rate of the wheels based on the vehicle speed and the wheel speed, then it controls the brake fluid pressure to reach the target slip rate.

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 3-modes: pressure reducing, pressure retaining, and pressure intensifying.

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 2 categories:
- Initial diagnosis: Done right after the engine starts and until the ABS indicator goes off.
- Regular diagnosis: Done 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





Self-diagnosis Table





Operation Mode Table

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.