Fail-safe Function
WARNING: This page is about a different car, the 2009 Honda S2000, 2008 Honda S2000, 2007 Honda S2000, and 2006 Honda S2000. 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 ECM ignores that signal, stores a DTC and turns on the MIL. The ECM will use a pre-programmed value for that sensor which allows the engine to continue running. This causes a DTC to be stored and the MIL to comes on.