Self-diagnosis Fault of Option Board

What does CPF21 mean?

A self-diagnosis fault was detected on the option board, potentially due to noise or spikes on the communication line or a defective option board itself. This indicates an internal issue with the option board's CPU, impacting its operation.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Replace the option board if the fault persists.

2. 4

   Replace the control board if the option board is confirmed functional.