Well, the chart below should help you know what part number to use for your Prius. My advice… buy new!
After multiple attempts at using used parts, with the proper part number and not… I am about to buy a new booster… the word is it’s best to replace both. Turns out, the false negatives from the Prius ECU have all led me down the wrong path. It’s the booster that goes bad folks. Replace that only first, even if it says, accumulator. Here is the chart to find your proper part number.