Symptoms are still two batteries
The usual picture: red triangle, P0A80, reduced power, a kind of limp — and the car still moves. Plenty of Gen 4s still get you to work like that. The other picture is a silent car and a dark dash. Gen 4 did not abolish the small 12-volt; start there, not with a traction pack. Symptoms.
If it is the pack conversation, scan with Dr. Prius and a Veepeak OBDCheck BLE before anyone quotes a replacement. That kit reads battery health. It is not an HV install, and we will not walk you through opening the pack.
Then the warranty fork
Toyota’s federal HV battery coverage is 8 years / 100,000 miles on 2019 and earlier cars, and 10 years / 150,000 miles on 2020 and newer. That is from Toyota’s 2020 announcement. Some states already had 10 / 150 on earlier cars under emissions rules. Check the glove-box warranty booklet for the car in front of you.
A 2016–2019 Prius that lived an easy life may already be past 8 / 100. A 2020–2022 that has not hit 150,000 miles is often still Toyota’s problem. In-warranty work goes to a dealer.
“Some states had 10 / 150 earlier” is real and messy. California and other emissions-state rules covered many earlier hybrids at 10 / 150. The glove-box booklet and a dealer warranty inquiry beat a blog table — including this one.
If you are actually out of warranty
The aftermarket for Gen 4 is thinner than Gen 2 / Gen 3. Greentec’s 2026 buying guide lists Gen 4 options in a band rather than a single SKU; we will not invent a tighter number than they published. Green Bean’s “most Prius replacements $1,349–$1,949 installed” line is their 2026 blog claim across Prius work — ask whether your year is in that band before you treat it as a quote.
NexPower’s widely listed GT2 prices in this guide are for Gen 2, Gen 3 / V / CT200h, and Prius C. Do not assume a Gen 4 sodium kit exists at those figures. If Salty Hybrid does not list your year, it is unknown here — not “coming soon” theater.
Dealer / RepairPal numbers still apply as the expensive baseline: $3,500–$5,000+ (Green Bean’s cited dealer range) and $4,501–$4,694 (RepairPal).
No fake countdown
We will not tell you the Gen 4 pack is “due.” Hybrid batteries wear with heat, cycles, and luck. Plenty of these cars will go well past the warranty odometer on the original pack. Plenty will not. Diagnosis, then a quote — not a pre-order.
Prius Prime and plug-in packs are a different battery. This site is Prius traction-pack guidance for the regular hybrid. Prime owners should treat every price on this site as non-applicable until a vendor quotes that specific pack.