System Features: Self-Diagnosis

The VSA control unit is equipped with a main CPU and a sub CPU. Each CPU checks the other for problems.
The CPU checks 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 VSA system 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 VSA control unit shifts to fail-safe mode.

Fig 1: Self-Diagnosis Chart

Courtesy of AMERICAN HONDA MOTOR CO., INC.