Buyer Research

2021 Toyota Prius — Should You Buy One?

Typical asking price: $20,000–$26,000. This is one of the more reliable vehicles in its class — here's what to watch for anyway.

Deciding between model years? Compare the 16 Toyota Prius years we've written up →

Kestrel Take

Six complaints and no recalls in five years. Six is not a record you can read reliability from in either direction — it means almost nobody has filed, and we say so rather than call the car clean. What the six contain is two surge-with-the-pedal-pressed reports of the kind that appear on every year of this generation, one owner who could not get a dealer to find where exhaust was getting into the cabin, and one hybrid battery that stops helping below six bars with nothing stored in the codes. The 2021 shares its hardware with the 2020 and sits outside the 2022's hybrid-shutdown software recall, which named 2022 cars only. Our checks come from the sibling years: the coolant level for the exhaust heat exchanger leak, the windshield, the 12V battery, and a look underneath for a catalytic converter shield. Buy one inside the 10-year/150,000-mile hybrid battery warranty, and let the price reflect that Toyota's 3-year bumper-to-bumper cover is gone or nearly so.

What we checked

Checked against public records, 2026-09-25

NHTSA holds 6 owner complaints for the 2021 Toyota Prius, and no recall campaigns.

That is too small a record to read a pattern from, so we are not going to pretend otherwise — with numbers this low one owner moves the percentage by a lot. What has been filed is grouped under the fuel system (2), the engine (2), throttle and cruise control (1). Treat those as things to look at, not as the vehicle's known weaknesses. A thin file usually means few of these were sold or few owners filed. It is not evidence the vehicle is trouble-free, and the issues below are our own research rather than a reading of this record.

Counts come from the NHTSA complaint and recall database — free, public, and worth checking yourself.

Known Issues for the 2021 Toyota Prius

Ranked by wallet impact. These are documented, recurring problems — not freak accidents. How we decide that.

Coolant burning off through a leaking exhaust heat exchanger — check the level before anything elseMedium

This generation warms the engine with an exhaust heat recovery unit and cools its EGR with a coolant-jacketed cooler, and both put engine coolant a wall away from hot exhaust. When either leaks internally, the coolant goes out the tailpipe: the reservoir drops with no puddle, the heater goes lukewarm, a check-engine light eventually appears, and a dealer finds the exchanger and, if it has gone on long enough, a catalytic converter soaked in coolant. Owners on the 2018 and 2019 pages describe it in detail and cite a Toyota bulletin for 2016–2019 cars; the 2021 is not named in it and nobody in this six-complaint record has filed it, so we are flagging the generation's known fault, not a proven 2021 pattern. Open the hood cold, look at the reservoir against the lines, and ask when it was last topped up.

Repair cost (estimate): $800–$2,000 for the heat exchanger or EGR cooler; $2,500–$4,500 if the catalytic converter needs replacing too

Source: not yet checked against public records.

Catalytic converter theft — the Prius is the thieves' favourite, and a replacement is four figuresMedium

Not a defect, but the most likely four-figure bill a used Prius owner faces. The hybrid's converter runs cool and stays rich in precious metals, thieves know exactly where it sits, and a 2021 without a shield is a two-minute job on a jack. A car that has already lost one is easy to spot: it starts with a roar like a straight pipe, and underneath there are fresh cut marks or a shiny new pipe section where the seller had it welded back. Ask whether a shield has been fitted and look for it — a flat aluminium or steel plate bolted under the front of the exhaust. If there is not one, price it into the deal; it is the cheapest insurance on the car.

Repair cost (estimate): $2,000–$3,500 for a replacement converter; $150–$300 for a shield that deters the next thief

Source: not yet checked against public records.

Windshield that cracks easily, and the camera calibration a replacement needsMedium

Windshield cracks lead the 2016 and 2018 Prius records — pebbles that would chip another car, cracks that start along the bottom edge overnight. The 2021 uses the same glass, and its six-complaint record cannot tell us whether the problem went away, only that nobody filed. What a buyer needs to know is that Toyota Safety Sense sees through this windshield, so a replacement is not a $250 aftermarket job: it needs camera-compatible glass and a recalibration, and a cheap install shows up later as pre-collision and lane-keep warnings. Check the bottom edge under the wipers and the area around the camera bracket, and if the glass has been replaced, ask for the invoice and look for the calibration line on it.

Repair cost (estimate): $400–$1,000 including camera recalibration

Source: not yet checked against public records.

12V auxiliary battery reaching the end of its lifeLow

The 12V battery under the rear cargo floor does not start the engine; it boots the car's computers so the hybrid battery can. When it weakens, the car shows a black screen or a wall of warnings when you press Power, and it can strand you as surely as a flat battery on any other car. Original units on this generation tend to last three to five years, which puts a 2021 right at the edge. Read the date on the battery, and take a hesitant or flickering boot on the first press as the sign it is due.

Repair cost (estimate): $120–$250

Source: not yet checked against public records.

Walk-Away Red Flags

✗Coolant reservoir below the low line on a cold engine, or weak heat from the vents
✗Any crack or repaired chip along the bottom of the windshield
✗Exhaust smell in the cabin with the windows up and the fan on
✗A roar on startup like a straight pipe, or fresh cut marks on the exhaust underneath
✗Slow or flickering boot on the first press of Power
✗State-of-charge bar that drops from full to two bars in a mile of city driving

Good Signs

✓Hybrid battery inside Toyota's 10-year/150,000-mile battery warranty, with the in-service date confirmed
✓Coolant at the full line on a cold engine and a clean tailpipe on a cold start
✓A catalytic converter shield fitted, with the receipt
✓Windshield replaced with Toyota glass and a camera calibration on the invoice
✓12V auxiliary battery replaced with a dated receipt
✓Toyota dealer service records through the 30,000-mile service