The am2 fuse blowing out, and the inverter overheating are two signs that the inverter pump is not working.
What is the purpose of the inverter pump?
What is an inverter on a Prius vehicle? An inverter converts the DC current coming from the Hybrid battery and converts it to a higher voltage.
And it also converts electricity from a higher voltage to a lower voltage. Since the inverter works directly with electricity, it retains a lot of heat.
If there is no way to cool down the inverter, then it will overheat. So that’s where the Prius inverter pump comes in.
The main purpose of the inverter pump is to circulate coolant to the inverter and its many components. The coolant will draw away heat from the inverter and prevent it from overheating.
Also, when there is an issue with the inverter pump, the Prius computer system will display the diagnostic code. The diagnostic warning code for an inverter pump issue is P0893.
Prius inverter pump failure symptoms
Any vehicle can break down for any reason. The inverter pump is an important part of a Prius. If it is not working as it should, there will be obvious signs that you will notice in no time.
When there is an issue with the inverter pump, your Prius will activate the check engine light. It may also turn on a different light which will look like a yellow triangle. Inverter pump issues are not something that should be ignored.
The inverter keeps overheating.
When the Prius pump does not work as it should, it will not be able to circulate coolant to the inverter and to other components in the system. Since cooling cannot reach these parts, the inverter will overheat. Then the check engine light will turn on.
Inverter pump sensors do not work
Sensors around the inverter and inverter components send information to the main module of the Prius’ computer. The computer then commands the inverter pump to pump coolant to cool down the inverter.
If the sensors do not pick up on the heat of the inverter, the inverter pumps will not pump coolant to cool down the inverter. It could be that the sensors fried because of the inverter overheating one or two times. The sensors have to be replaced.
The am2 fuse blows out
The scariest aspect of the am2 fuse blowing out randomly is that when it blows, your Prius will immediately stall. You could be on the freeway and it will start shutting down out of nowhere. So why does the am2 fuse blow out?
One reason why the am2 fuse shorts out, especially in Prius, is because the inverter becomes too hot. When you check on the fuse, the metal side pieces will have a light burnt color.
You can replace the fuse, but you must find the reason why the inverter pump is not working. If you simply replace the fuse and don’t check on the pump, the am2 fuse will blow again.
How to check a Prius inverter pump
Turn on your Prius and leave it in park. Wait a few minutes for the engine to warm up. Open the hood of your Prius and prop the hood open.
Locate a long and slightly orange container next to the Prius battery. Remove the small circular plug and look inside the water pump container. The water should be moving slightly.
This means the pump is not working and will not pump coolant into the system.
Cost of replacing an inverter pump
The average price of an inverter pump is around $250. Now you must add the cost of labor. A typical mechanic will charge around $450 for the labor and the parts.
If you take your Prius to a Toyota mechanic, they will find every opportunity to charge you more. But since they are trained by Toyota, they will know exactly how to fix your Prius.
They can also find out why the inverter pump stopped working and give you tips on how to care for it.
If you take your Prius to a non-certified mechanic, their prices may be cheaper.
You will have to find one that knows how to repair and care for hybrid vehicles as many mechanics still do not know how to do this. They won’t be able to tell you how to prevent your inverter pump from malfunctioning in the future.
Prius Inverter pump Recall
In 2018, the Toyota motor engineering Factory sent out a recall notification to certain Toyota Prius models. The models were between 2010 and 2014 for the Toyota Prius and 2012 to 2014 for the Toyota Prius 5.
The reason the Toyota company sent out recall notifications was that these vehicles were installed with faulty power inverters. The main issue with the power inverters was that the system allowed too much electricity to flow through the IPM or the intelligent power module.
This issue caused Prius and Prius 5 to shut down. If you own a Prius and Prius 5, you may have been driving with a faulty inverted pump or faulty inverter.
There’s also a separate recall in 2009 specifically for the inverter pump. It appears that it was common for inverter pumps to fail in second-generation Toyota Priuses.
Many of the inverter pump failure questions and information on the internet pertain mostly to the second-generation Priuses. It seems like it is an ongoing issue.
The reason why these inverted pumps had to be recalled is that the pumps allowed air inside the coolant system.
There would be sections of the coolant system that only pumped air, not coolant. Air in the coolant pump system means that the system could not cool down the inverter.
The two most common symptoms of a failed inverter pump are the inverter overheating and the am2 fuse blowing out. You can check on the inverter pump by opening the pump container located in the middle of your Prius.
The cost to replace an inverter pump can be as high as $450. There have been several inverter pumps and inverter recalls in the last 10 years.