If you see these faults, and the powertrain control module (PCM) reports code P0128 your thermostat may be defective.
If your vehicle is under warranty, the thermostat will be replaced. The defective thermostat has a seal that becomes dislodged as shown in the following photo.
The replacement procedure includes removal of the rear trunk tub (the factory service tray is shown in place).
More information: Acura Technical Service Bulletin 17-048
Photo credits: Terrence B, Travis D.