Product Specifications
- Product type: Electric inverter coolant pump
- Vehicle system: Hybrid inverter cooling circuit
- Drive type: Electric
- Coolant ports: Two
- Mounting bracket: Included
- Engine application: 1.5L 1NZ-FXE hybrid
- Package quantity: One pump assembly
- Installation location: Engine compartment near the inverter cooling circuit
- Warranty: Seller-stated lifetime warranty
The warranty language comes from the seller. Review its exclusions, return requirements and replacement terms before purchase.
What Does the Prius Inverter Water Pump Do?
The pump circulates coolant through the Prius hybrid electronics cooling circuit. This loop helps remove heat from components that include the inverter and converter assembly.
The inverter converts electrical power between the high-voltage hybrid battery and motor-generators. That process generates heat, particularly during acceleration, regenerative braking and sustained vehicle operation.
The cooling circuit typically includes:
- Inverter and converter assembly
- Electric inverter coolant pump
- Dedicated heat exchanger
- Inverter coolant reservoir
- Coolant hoses and pipes
This circuit is separate from the engine radiator loop. Replacing the inverter pump will not repair a failed engine water pump, thermostat or engine-side coolant leak.
Common Symptoms of a Failed Prius Inverter Pump
Possible symptoms include:
- Red master-warning triangle
- Hybrid-system warning
- Check Engine Light
- P0A93 diagnostic trouble code
- “Inverter Cooling System Performance” fault
- Reduced hybrid performance
- Vehicle entering fail-safe operation
- Hybrid system shutting down
- Little or no coolant movement in the inverter reservoir
- Pump that remains silent with the vehicle in READY mode
A failed inverter pump does not always cause the gasoline engine temperature gauge to rise. The protected component is the hybrid inverter, not the 1NZ-FXE engine.
How to Check Inverter Coolant Circulation
With the vehicle safely in READY mode, coolant movement should normally be visible in the inverter reservoir when the pump is operating. Look for circulation or turbulence rather than relying only on pump noise.
No visible movement may indicate:
- Failed inverter pump
- Blown fuse
- Damaged wiring
- Disconnected electrical connector
- Air trapped in the circuit
- Restricted coolant hose
- Incorrect coolant level
Keep hands, tools and clothing away from moving parts while checking the system. Do not open the reservoir when the coolant is hot.
If coolant is disappearing, use our guide on how to find a coolant leak to inspect hoses, connections, reservoirs and heat exchangers.
P0A93 Does Not Automatically Prove the Pump Is Bad
P0A93 indicates inadequate inverter cooling performance. A failed pump is a common cause on the second-generation Prius, but diagnosis should also cover:
- Pump power and ground
- Related fuses
- Electrical connector condition
- Inverter coolant level
- Air trapped after service
- Blocked or kinked hoses
- Restricted inverter radiator
- Damaged inverter cooling components
Confirm pump operation and coolant circulation before replacing parts. The parts cannon is already expensive enough on normal cars; hybrids simply add more voltage.
Toyota Inverter Water-Pump Recall
Toyota issued Safety Recall C0U under NHTSA campaign 12V-536 for certain 2004–2009 Prius vehicles. Toyota reported that damaged motor-coil insulation could allow corrosion, pump stoppage or an electrical short. In some cases, an opened fuse could cause the hybrid system to stop while driving.
Before purchasing a replacement, check the VIN through:
Do not assume every 2004–2009 Prius still qualifies for a free replacement. The vehicle may already have received the campaign repair. Recall status is determined by VIN and Toyota’s service records.
The original defect report is available through the NHTSA 12V-536 recall documentation.
Installation and Hybrid Safety
The pump is part of a low-voltage coolant circuit, but it is installed near high-voltage hybrid components. Do not disconnect, probe or handle orange high-voltage cables without the required training and safety equipment.
General installation steps include:
- Make the vehicle completely safe and prevent READY-mode activation.
- Remove the key or move the smart key away from the vehicle.
- Disconnect the 12-volt battery as directed by Toyota service information.
- Allow the cooling system to cool.
- Drain or clamp the inverter coolant circuit as appropriate.
- Disconnect the pump’s electrical connector.
- Remove both coolant hoses.
- Remove the old pump and bracket.
- Install the replacement in the correct flow direction.
- Reconnect the hoses and electrical connector.
- Refill with Toyota-approved coolant.
- Bleed air from the inverter cooling circuit.
- Verify visible reservoir circulation.
- Check for leaks and clear stored codes.
- Road-test and rescan the hybrid-control system.
Follow the Toyota repair manual for the exact bleeding and safety procedure. Coolant is toxic, so collect it properly and keep it away from children and animals.
For general coolant-service principles, see our guide on how to flush a car cooling system.
Bleeding the Prius Inverter Cooling Circuit
Air trapped in the inverter loop can reduce circulation and trigger a repeat cooling-system fault even when the new pump works correctly.
After installation:
- Fill the inverter reservoir with the specified coolant.
- Activate the pump according to Toyota service procedures.
- Open the appropriate bleed point when required.
- Watch the reservoir for bubbles and circulation.
- Maintain the proper coolant level.
- Continue until air bubbles stop.
- Inspect every connection for leakage.
- Recheck the level after the vehicle cools.
Do not confuse the inverter reservoir with the engine coolant reservoir. They serve different circuits and diagnosing the wrong tank is a surprisingly efficient waste of an afternoon.
Frequently Asked Questions
What years does G9020-47031 fit?
It fits the second-generation 2004–2009 Toyota Prius with the 1.5L hybrid powertrain.
Does it fit the 2007–2009 Prius Touring?
Yes. The Touring trim uses the same second-generation hybrid platform, subject to VIN and OE-number verification.
Is this the engine water pump?
No. It circulates coolant through the hybrid inverter cooling system. The gasoline engine uses a separate water pump.
How many coolant ports does the pump have?
The assembly has two coolant hose ports.
Is the mounting bracket included?
The supplied listing states that the bottom mounting bracket is included. Confirm the package contents before ordering.
What code can a failed inverter pump cause?
P0A93, commonly described as inverter cooling-system performance, is frequently associated with inadequate inverter coolant circulation.
Can a failed inverter pump stop the car?
Potentially. Toyota’s recall documentation states that certain failures could stop the pump, illuminate warnings and, in limited cases, open a fuse that could shut down the hybrid system.
How can I tell whether the pump is circulating coolant?
With the car safely in READY mode, movement should generally be visible in the inverter coolant reservoir. No movement requires further pump, fuse, wiring and coolant-level diagnosis.
Was this pump involved in a recall?
Certain 2004–2009 Prius vehicles were included in Toyota Safety Recall C0U/NHTSA 12V-536. Check the VIN to determine whether the campaign applies or has already been completed.
Can I use universal coolant?
Use coolant meeting Toyota’s specifications for the vehicle. Mixing incompatible coolant can create deposits, reduced corrosion protection or sealing problems.
Does replacing the pump automatically clear P0A93?
Not necessarily. Air must be removed from the circuit, circulation must be verified and stored diagnostic codes may need to be cleared with a capable scan tool.
Toyota’s OE catalog identifies G9020-47031 as a drive-motor inverter cooler water pump.
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