MajorCommonElectrical

Toyota Prius: ZVW50 Inverter Electric Water Pump Failure

ZVW50 Inverter Electric Water Pump Failure is a common electrical fault on the Toyota Prius on the 2015–2021 cars, and we rate it major. Putting it right costs $450 to $950 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: 2015–2021
Fuel: hybrid
Gearbox: cvt
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 of the Water pump yet. We would rather show none than show a picture of a different part.

What goes wrong

The ZVW50 Prius (fourth generation) employs a dedicated brushless electric water pump to circulate coolant through the power control unit (PCU), which integrates the boost converter, MG1 inverter, and MG2 inverter into a single assembly. The pump's bearing and impeller are subject to wear from continuous low-speed operation and are known to fail between 80,000 and 150,000 km. Loss of PCU cooling triggers the inverter's thermal protection circuit, reducing available hybrid power immediately, and sustained loss of cooling without intervention can result in PCU damage costing several thousand dollars to rectify.

What you would notice

Master warning triangle with 'Check Hybrid System' message on multi-information display
Abrupt reduction to reduced-power mode, particularly after highway driving
P0A93 or inverter over-temperature DTC logged in PCU ECU
Inverter coolant reservoir found low without external leak

How to check it

Where to look. Engine bay, passenger side, adjacent to the PCU/inverter assembly

With ignition switched on, listen for the electric water pump audible hum from the engine bay — absence suggests pump failure.
Scan for P0A93 (inverter cooling system performance) or related PCU thermal DTCs.
Check coolant level in the dedicated inverter reservoir (separate from the engine circuit).
Inspect the pump electrical connector for corrosion or spread terminals.

Parts involved: Water pump.

What it costs to put right

$450 to $950 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 inverter cooling system ever been serviced or the electric water pump replaced?”
“Has a 'Check Hybrid System' warning ever appeared during ownership?”
“Is the inverter coolant reservoir full and free of discolouration?”

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 published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Toyota Prius buyer questions

Is zvw50 inverter electric water pump failure serious on a Toyota Prius?

We rate it major and common on the Toyota Prius. The ZVW50 Prius (fourth generation) employs a dedicated brushless electric water pump to circulate coolant through the power control unit (PCU), which integrates the boost converter, MG1 inverter, and MG2 inverter into a single assembly. The pump's bearing and impeller are subject to wear from continuous low-speed operation and are known to fail between 80,000 and 150,000 km. Loss of PCU cooling triggers the inverter's thermal protection circuit, reducing available hybrid power immediately, and sustained loss of cooling without intervention can result in PCU damage costing several thousand dollars to rectify.

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

$450 to $950 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 2015–2021 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?

With ignition switched on, listen for the electric water pump audible hum from the engine bay — absence suggests pump failure. Scan for P0A93 (inverter cooling system performance) or related PCU thermal DTCs. Check coolant level in the dedicated inverter reservoir (separate from the engine circuit). Inspect the pump electrical connector for corrosion or spread terminals. Look here: Engine bay, passenger side, adjacent to the PCU/inverter assembly