Engine Maintenance Mode
So today my wife's Clarity PHEV decided to idle the ICE for about 15 minutes. Full battery and I watched the car's power flow display showing the ICE providing a little power. The car showed it was in EV mode even though I could hear and "see" the ICE running.
Bottom line, Honda implemented an Engine Maintenance Mode to ensure the ICE runs periodically to lubricate seals and check for pressure leaks.
2018 Honda Clarity Touring PHEV - Forest Green w/Tan interior (wife's car)
2017 Volt LT - Heather Gray; black bow ties, Charcoal VoltShelf
2012 Cruze ECO MT (hail totaled 5/8/17 103,600 miles @42.5 MPG)
2010 Mit Lancer GT MT (traded for ECO @31K miles)
2002 Pont Montana AWD - title to son at college graduation
1990 Pont Transport (traded for Montana @240K miles)
1986 Fiero GT MT (traded for Transport - needed more seats)
1985 Fiero 2M4 MT (traded for Fiero GT @8K miles)