flat battery

[ian rooke]

Just tried ti start my Gen 4 prius 12 v Battery is flat ,started car with Battery pack car started but I have 2 warnings .pre-crash fault and hybrid fault is there any way to reset or is it a dealer fix .I assume it is just a reset problem 

[Joseph D]

See if resets after 2 or 3 start/drive cycles.  Otherwise a visit to some who can read the codes, make a note of what the codes are, and then rest them will be required.  You may need to do some remedial work, depending on what codes come up.

[ian rooke]

Thanks Joseph D took the car out for a 20 minute drive turning on and off 3 times and faults cleared one by one, good to know though

[PeteB]

When my 2016 Prius has this problem at 18  months old, I had to jump start several times over a couple of months and sometimes I had 5 or 6 warnings, and various safety systems and the cruise control would not operate until the faults cleared.  Sometimes they took 10-12 restarts before all of them cleared.

My dealer then tested the 12V Battery and said it was faulty, so they replaced it under warranty after which I had no more problems.

[QuantumFireball]

It seems fairly common that a Prius will throw spurious errors if the 12V Battery is low. Not uncommon with modern cars in general.