An inverter pump failure is one of Toyota Prius owner’s worst nightmares. The car will start fine, drive for a while, and stop working. Sometimes, you’ll need to keep turning the engine off and on to continue driving.
There are several symptoms of a malfunctioning Prius inverter pump. Some include check engine light on the dash, overheating, coolant leaks, and blown-out AM2 fuse. So, what should you do if your Prius has these warning signs?
Thankfully, this guide discusses 5 Prius inverter pump failure symptoms. You’ll also discover their causes, how to troubleshoot them, and more.
Role of the Inverter Pump on a Prius Car
The inverter on your Prius car generates heat while converting DC from the battery to a higher voltage. It might also heat up when converting electricity from a higher to a lower voltage. An overheated inverter will cause the engine to lose power and stall.
The inverter pump’s role is to cool down the heated inverter and ensure efficient operation. The inverter pump circulates the coolant to draw away any heat accumulating on the inverter.
Answer: How to Check for a Functional Prius Inverter Pump
Are you wondering what to expect from a functional Prius inverter pump? If so, turn on the engine and allow it to warm up for a few minutes.
Then, open the hood and locate an orange container. This container is near the battery and serves as the water pump container.
Remove the plug on the container and check inside. If the water appears to move slightly, your pump is functional.
Alternatively, touch the water pump container with your finger or stick. If there’s a vibration, the pump should be working.
Prius Inverter Pump Failure Symptoms
Your Prius vehicle might break down due to the inverter pump failure. But before the car breaks down, you might notice some warning signs.
Below are the common symptoms of an inverter pump failure on your Prius car:
Check Engine Light
The check engine light on the dash is the most common symptom of Prius inverter pump failure. In this case, your Prius will turn on, illuminate the check engine light and fail to drive forward or reverse.
A P0A93 fault code comes with the check engine light to indicate issues with the inverter pump. Failure to troubleshoot a defective inverter pump might lead to severe damage and costly repairs.
With excessive use over time, the inverter pump might succumb to wear and reduce its effectiveness. If the pump fails, the inverter overheats, causing the Prius system to illuminate the warning light. So, how can you troubleshoot a warning light resulting from a pump failure?
If you see a warning light on the dash, allow a mechanic or dealer to inspect and address the issue.
Below are the tricks to use if you’re driving and this warning light pops up:
- Turn the car off and wait for 10-15 minutes. The goal is to allow the inverter to cool down before starting the engine again.
- Reset the battery by disconnecting it for at least 15 minutes.
- Use a diagnostic code reader to clear the warning light and the fault code.
These tricks allow you to limp your Prius to the nearest repair shop.
Overheated Inverter
A Prius inverter pump that does not work as it should causes the inverter to overheat. The pump won’t circulate coolant to cool down the inverter and other components.
An overheated inverter will cause the check engine light to turn on. If you try to accelerate the car, it’ll lose power gradually and go into the ‘limp home mode’ to protect the engine from catastrophic damage.
Your professional technician will diagnose the pump to know if it requires replacing. Replacing a failing Prius inverter pump solves the overheating problem.
Sometimes, your dealer might recommend a software update to troubleshoot a Prius inverter pump failure. Luckily, Toyota has provided several software updates related to the inverter pump failure to help improve the pump’s performance.
Coolant Leaks
Over time, the Prius inverter pump wears out, or parts get damaged, causing coolant to leak. You might notice colored fluid on the garage floor, indicating leaking coolant from the Prius inverter pump.
Coolant leaking from the pump can land on the battery pack or other electrical components. When this happens, your car might experience short circuits and other electrical issues. Moreover, this leakage leaves the pump with less coolant to cool down the inverter. As a result, the inverter overheats and causes the car to lose power and stall.
If your Prius has a coolant leakage issue, take it to a specialist for inspection. If a worn-out or damaged pump is to blame, the specialist might repair or replace it.
Blown-Out AM2 Fuse
The AM2 fuse is part of your Prius ignition system. If the AM2 fuse blows out while driving, the car stalls and fails to start again.
The AM2 can blow out due to several reasons. One of them is an overheated inverter, particularly in Toyota Prius cars. A blown-out AM2 fuse appears burnt on the metal side pieces. You may also see smoke and smell burnt plastic when the AM2 blows.
Locate the fuse and replace it if blown out. But replacing the fuse alone won’t resolve the root cause. So the fuse may blow out again. In this case, you’ll need to examine the inverter pump as it’s the possible culprit. Have the pump repaired or replaced, and ensure the car has sufficient coolant.
Fried Inverter Pump Sensors
The inverter pump sensors pick information from the inverter and send it to the Prius’ ECU. Then, the ECU commands the pump to circulate coolant to cool the inverter and surrounding components.
If the sensors are faulty, they do not send information to the Prius’ computer, and the inverter pump does not pump coolant. As a result, the inverter tends to overheat. Like other Prius inverter pump failure symptoms, your car will gradually lose power and stall.
An overheated inverter will eventually fry the inverter pump sensors. When this happens, the pump won’t circulate coolant to cool the inverter.
You can fix this issue by checking for fried sensors and replacing them if necessary. Then, diagnose the inverter and the pump to identify the underlying problem.
Question: How Much Does it Cost to Replace the Prius Inverter Pump?
The cost of replacing your Prius inverter pump will vary from dealer to dealer. Since a new inverter pump will cost around $250, expect to pay between $300 and $400 for the pump and labor.
The goal is to find a dealer or mechanic who can diagnose and fix hybrid vehicles.
Professionals from Toyota will charge you more, but you can rest assured they’ll replace the pump and check why it failed. They can also advise you on how to care for the pump.
Answer: How to Maintain Prius Inverter Pump
You can prevent Prius inverter pump failure through proper maintenance. Below are the tips for maintaining the inverter pump:
- Check the coolant level: The inverter pump requires sufficient coolant to work properly. If the coolant level is low, refill the reservoir as the owner’s manual recommends.
- Change the coolant: The coolant deteriorates after excessive use and loses effectiveness. With deteriorated coolant, the inverter will overheat and damage the inverter pump sensors. So, change the coolant as recommended in the owner’s manual.
- Do a coolant flush: When replacing the coolant, conduct a coolant flush to remove any deposits accumulating over time. Deposits such as rust, dirt, and sludge build up in the inverter pump and coolant system and block the smooth flow of coolant. You can use a cooling system flush to remove the deposits.
- Regular software updates: Consult with your dealer if your Prius’ inverter pump requires a software update to improve its performance.
Final Thoughts
Hopefully, this guide helps you know the common Prius inverter pump failure symptoms. The most reported symptoms are inverter overheating, check engine light, blown-out AM2 fuse, coolant leaks, and fried inverter pump sensors.
If your Toyota Prius experiences these symptoms, troubleshoot the underlying problems to prevent further damage. Then, maintain the inverter pump and cooling system to prevent these symptoms from occurring.