HSI

This thread on PriusChat introduced the required PID to evaluate the power meter of the HSD system.
Here is the HV System Indicator, as it's called:

HSI can be used for a better detection of the Glide condition and for additional analisys on Power/ECO usage.
Add this PID to your Torque to use the HSI:

Name	ShortName	ModeAndPID	Equation	Min Value	Max Value	Units	Header
HV System Indicator	H S I	212B	{A:0} * 256 + B - {A:1} * 512	-512	511	%	7C0

You can also use the PID csv file provided in the download section of this site.

Some notable values are:

Zone Name	Mark	Value	Gear Stick Position
PWR	-	> 100	D
ECO - PWR		100	D
Upper ECO	5	83	D
Upper ECO	4	69	D
ECO	3 (center)	50	D
Lower ECO	2	35	D
Lower ECO	1	16	D
ECO - CHG	0 (rest)	0	D
CHG	-	< 0	D
CHG	bottom	-100	D
Any	-	-512	P, R, N