Cranky Prius

26 January 2015  

By Jim Gilmour

P0A0F – Engine Failed to Start

I asked him to go back in with the diagnostic tool and give me some high voltage battery data. The battery State of Charge (SOC) was down to just 18%, which is critically low; the normal SOC ranges between 30% and 80%.

The engine in the Prius is started by Motor Generator 1 (MG1) in the transmission. During start-up, the valve timing is adjusted so that the inlet valve is closed at 78° before TDC, this gives very light compression and with the throttle open, very little pumping losses on the induction stroke.

So now the mystery was solved, but the bad news was that the battery was very low on charge and our friend now had the job of diagnosing the non-start problem without too many chances to crank the engine.

Have you ever experienced something like this that you’d like to share, or have any comments?