Traction Control System (TCS)

ABS Features





When the brake pedal is pressed while 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.

TCS Features





The TCS provides low speed traction. When a drive wheel loses traction on a slippery road surface and starts to spin, the ABS/TCS control unit sends a brake signal to the modulator unit, which applies brake pressure to slow the spinning wheel. At that time, the ABS/TCS control unit sends an engine retard signal to the PCM to prevent damage to the transmission.

ABS Main Control





The ABS/TCS 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/TCS 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 intensifying, pressure retaining, and pressure reducing.

TCS Main Control





The ABS/TCS control unit controls the TCS based on signal inputs from the throttle position sensor, engine speed sensor, shift position sensor, and the wheel sensors. In addition, the ABS/TCS control unit sends an engine retard request signal to the PCM if necessary. The ABS/TCS control unit uses the modulator unit to control the TCS. The pressure intensifying control has three modes: pressure intensifying, pressure retaining, and pressure reducing.

ABS Self-Diagnosis
- The ABS/TCS control unit is equipped with a main CPU and a sub CPU. Each CPU checks the other for problems.
- The CPUs check the circuit of the system.
- Self-diagnosis can be classified into two categories:
- Initial diagnosis: Done right after the engine starts and until the ABS or TCS indicator goes off.
- Regular diagnosis: Done right after the initial diagnosis until the ignition switch is turned OFF.
- When a problem is detected by self-diagnosis, the ABS/TCS control unit shifts to fail-safe mode.





ABS Self-diagnosis Table





ABS Operation Mode Table

On-board Diagnosis Function
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.


TCS Self-diagnosis
- The ABS/TCS control unit is equipped with a main CPU and a sub CPU. Each CPU checks the other for problems.
- The CPUs check the circuit of the system.
- Self-diagnosis can be classified into two categories:
- Initial diagnosis: Done right after the engine starts and until the ABS or TCS indicator goes off.
- Regular diagnosis: Done right after the initial diagnosis until the ignition switch is turned OFF.
- When a problem is detected by self-diagnosis, the ABS/TCS control unit shifts to fail-safe mode.





TCS Self-diagnosis Table





TCS Operation Mode Table

On-board Diagnosis Function
The TCS 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 Tester user's manuals for specific operating instructions.