MajorCommonElectrical

Toyota Prius: Hybrid battery (NiMH) degradation and end-of-life failure

Hybrid battery (NiMH) degradation and end-of-life failure is a common electrical fault on the Toyota Prius on the 2003–2015 cars, and we rate it major. Putting it right costs $1,500 to $4,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 42 documented faults on the Toyota Prius.

Vehicle: Toyota Prius
Years: 2003–2015
Fuel: hybrid
System: Electrical

This page covers the Toyota Prius as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Toyota Prius faults42 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph for this fault yet. We would rather show none than show a picture of something else.

What goes wrong

The nickel-metal-hydride traction battery in Gen 2 (XW20) and Gen 3 (XW30) Prius degrades with age, typically failing between 10 and 15 years or 150,000-250,000 km. Individual cell modules drift out of balance, triggering the red triangle warning and P0A80 code, and the car falls back on the petrol engine with poor economy. NZ has a mature refurb industry: reconditioned exchange packs run roughly $1,795 (3-month warranty) to $3,395 (24-month warranty), while a new genuine pack fitted is $2,000-$4,500. The original 8-year Toyota battery warranty has expired on all cars in this year range.

What you would notice

Red triangle / master warning light with hybrid battery icon
Fuel economy noticeably worse than ~4.5-5.5 L/100km
Battery gauge swinging rapidly from full to empty
Petrol engine running almost constantly, even at idle
Weak electric-only crawl in car parks

How to check it

Where to look. Traction battery pack under/behind the rear seat, accessed from the boot

On the test drive watch the energy monitor screen: a healthy pack charges and discharges smoothly, a dying one jumps between nearly full and nearly empty within a couple of minutes.
Ask the seller to let the car sit in READY mode - the engine should cycle off; if it never stops running, be suspicious.
Ask for a Dr Prius app battery report or a hybrid-shop health check, and ask for the invoice if the pack has already been replaced (a refurb warranty may transfer).

What it costs to put right

$1,500 to $4,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the hybrid battery ever been replaced or reconditioned, and is there an invoice?”
“What real-world fuel economy does it get around town?”
“Has the red triangle warning ever appeared?”

Now check the Toyota Prius you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

Taha Auto Group NZ hybrid battery replacement cost guide
hybridbatteries.co.nz NZ 2026 price guide
PriusChat P0A80 battery failure threads
Grimmer Motors Hamilton Prius battery replacement page

Toyota Prius buyer questions

Is hybrid battery (nimh) degradation and end-of-life failure serious on a Toyota Prius?

We rate it major and common on the Toyota Prius. The nickel-metal-hydride traction battery in Gen 2 (XW20) and Gen 3 (XW30) Prius degrades with age, typically failing between 10 and 15 years or 150,000-250,000 km. Individual cell modules drift out of balance, triggering the red triangle warning and P0A80 code, and the car falls back on the petrol engine with poor economy. NZ has a mature refurb industry: reconditioned exchange packs run roughly $1,795 (3-month warranty) to $3,395 (24-month warranty), while a new genuine pack fitted is $2,000-$4,500. The original 8-year Toyota battery warranty has expired on all cars in this year range.

How much does it cost to fix on a Toyota Prius?

$1,500 to $4,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Toyota Prius years are affected?

Our research records this fault on the 2003–2015 Toyota Prius. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

On the test drive watch the energy monitor screen: a healthy pack charges and discharges smoothly, a dying one jumps between nearly full and nearly empty within a couple of minutes. Ask the seller to let the car sit in READY mode - the engine should cycle off; if it never stops running, be suspicious. Ask for a Dr Prius app battery report or a hybrid-shop health check, and ask for the invoice if the pack has already been replaced (a refurb warranty may transfer). Look here: Traction battery pack under/behind the rear seat, accessed from the boot