In the past month the P Lock malfunction (07 Prius) indicator light has come and stayed on. Twice in the past month after going into a store it would not start. After waiting around 5 minutes and pressing the start button a bunch of times it finally started. The battery reads 12.17 volts. I disconnected the battery to see if it would reset the malfunction indicator. It did not and I am worried one of these days it won't start at all. Any suggestions?
That error message is a classic low 12V problem, as is your startup problem. Either fully charge the battery, and make sure the connections are tight, or replace it now if it is old. Your reading of 12.17 volts does not give any confidence in the viability of the present battery.
To put it another way, the P Lock problem isn't causing the starting problem--they're both symptoms of the battery condition.
That's what I've been reading which is why I checked the battery. Sounds like any kind of load may be dropping it under 9 or 10 volts. The battery is 8 yrs old. Will change it and see what happens. Thanks!