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.

Fig 1: ABS Self-diagnosis Table

Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE:

At the DTCs with "*" mark, there are cases that the ABS/TCS control unit shifts to fail-safe mode A1, L1 when the ABS/TCS control unit detects more than one DTC and for different wheel.
If the ABS/TCS control unit detects the DTCs which have different fail-safe mode individually, the ABS/TCS control unit take priority the large number mode.