Toyota prius Owner's Manual page 503

Have the vehicle inspected immediately.
Failure to investigate the cause of the following warnings may lead to
the system operating abnormally and possibly cause an accident.
Have the vehicle inspected by any authorized Toyota dealer or
repairer, or another duly qualified and equipped professional immedi-
ately.
Warning message
(If equipped)
PRIUS_OM_OM47871E_(EE)
Details
Indicates a malfunction in the LED headlight system.
Indicates a malfunction in the P position control sys-
tem.
In this situation, there is a possibility that the parking
lock mechanism will not work.
When parking, park the vehicle on a flat surface and
apply the parking brake securely. Also, it may not be
possible to turn the "POWER" switch off. If this hap-
pens, applying the parking brake will enable the
switch to be turned off.
5-2. Steps to take in an emergency
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