Fail-safe Function
WARNING: This page is about a different car, the 2006 Honda Odyssey and 2005 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.
When an abnormality occurs in the signal from a sensor or from another control unit, the PCM ignores that signal and assumes. This causes a DTC to be stored and the MIL to come on. Pre-programmed value, for them that allows the engine to continue running.