Toyota 2013 Prius Owner's Manual page 578

Warning message
Warning message in radar cruise mode (if equipped)
■
In the following cases, the warning message may not be displayed even if
vehicle-to-vehicle distance decreases:
When your vehicle and the vehicle ahead are traveling at the same
●
speed or the vehicle ahead is traveling more quickly than your vehicle.
When the vehicle ahead is traveling at very low speed.
●
Immediately after cruise control speed is set.
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At the instant the accelerator pedal is depressed.
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PRIUS PHV_OM_OM47787U_(U)
5-2. Steps to take in an emergency
Details
The fuel filler door has been
left open.
The charging port lid is open.
Correction
procedure
Tighten the fuel
tank cap and close
the fuel filler door.
Close the charging
port lid.
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