How to Replace the Inverter Coolant Pump

My 2005 shut down this past December with the red triangle. I had it towed to my wife's warehouse. It has been bitter cold for the past 3 weeks and today was my 1st chance to do the fix. Fuse AM2 kept blowing(2nd blue fuse from the top right on pic 9). I removed the battery and charged it for a week while I figured out what to do. I put the battery back in to diagnose the problem and the car started without a problem. I could move it, but I refrained from leaving the parking lot because I had smelled burnt plastic when the call first stopped on me.

Now, I had a car with that could run but I knew something like the pump must have died. I got the pump from Champions of Houston for $87 and change. I waited until today to start fixing it because it was the 1st day above 60 degrees in the past 2 weeks for us that I had time at home.

I agree, I would also add removing the headlight assembly would make life a whole lot easier. Going through the hood is too much trouble. You are more apt to do damage to yourself and the car.

Just removing the headlight would make this an easy job. This method will probably be my method when I need to fix the headlights too. I did the whole job in 1.5 hours. First hour was following the original instructions. I stopped when I could not get the hoses off the old pump. I would start by removing the bumper and then the headlight assembly. The 2nd picture shows how much room there is to work when you take this step. Now removing the electrical connector and 2 hoses is a snap.

3rd and 6th pic shows the damage done by the pump and the source of the burnt plastic smell. It was easier to remove the pump from the assembly than to remove the whole assembly from the car. This is shown in the 4th and 5th pictures. pictures 5,6, and 7 are a comparison of the damage and to new pump. Pictures 8,9,and 10 are the completed pics prior to putting the headlight assembly back on. This job should take less than an hour and you should only need a 10mm socket, channel lock/pliers and some extensions.


I am glad to learn on my 2005 since my wife has a 2008 and I will need to maintain it.

Here are my pics

 

The AM2 fuse blowing seemed to be caused by the overheating due to the failure of the Inverter pump. I prefer fuse blowing than the Inverter. The blowing of the fuse stopped after the removal, recharge and reinstallation of the 12V battery. Car ran fine after the battery was reinstalled. I just did not drive very far. Fuse did not blow after the the 12V battery service and prior to the replacement of the inverter. I just replaced the inverter today. The car sat for 3 weeks. 1 week for the battery and 2 weeks for good weather for to replace the pump. I could have driven it the past 2 weeks, but did not want to risk damage to the inverter and paying for a tow again. Total cost was $80 for the tow, $87 for the pump and $20 for coolant. I am glad I did it myself and am not too afraid of working on the Prius anymore.

I had planned to change the inverter pump, but it failed before I could get to it.

 

Inverter did not fail.

214K miles. Way out of warranty

AM2 fuse do not blow due to Inverter failure. It blew because of overheating after the failure.




AM2 fuse blew after Inverter pump failure. I replaced the fuse and the fuse blew evertime after the 1st day. 3 days later, after the tow, I removed the 12v battery and recharged it. 7 days later I put the battery back and replaced the AM2 fuse. The 2005 started and moved like nothing had happened. The bad inverter pump is still in the car for 2 more weeks.

I knew something was still wrong so I looked into the inverter pump replacement where I found this tread.
priuschat.com/forums/gen-ii-prius-care-maintenance-troubleshooting/47846-no-start-after-smoke-burning-smell-front.html
(I can not add links until 5 posts)
I tried testing the pump and saw no flow in the coolant and the proximity I could smell the plastic smell that occurred that night.
This is when I decided the inverter pump is the root cause of the problems my 2005 was having.

 

This sounds like a carbon copy of the problems we were having with our 2004 in the 700 miles from home, help! thread and the dealer didn't mention anything about the coolant pump. Should I have them take another look at it, or should I poke around in there to see if I can see anything?

 

I tried to see if there was any codes, but my reader showed nothing and it is just a general OBD2 reader. I suspected the pump because on IG-on but not Ready there was not sound from the pump. When I changed pumps, I tested immediately and felt water move under the hoses. That was when I knew I had gotten it. I used this thread and the one above to solve my problems. If there is no sound and no water flow on the hose when you turn the car into IG-on like Patrick said, then it has probably stopped working.

If a dealer had looked at it, they would probably had sent me on my way after the battery was removed and reinstalled. This is a simple procedure and cost is not too bad. These pumps probably can only go 100k at the most and should be a put on preventative maintenance list.

It is a lot easier than doing a timing belt. It is just a tad harder than changing radiator hoses. If you can turn a 10mm socket, you can probably do it yourself.

 

I put ign on, and pump doesn't run. Hooked up to batt terminal and a grounded .bracket, still no run, but makes spark when completing circuit by touching ground to eng block. Tried same with new one, same results. Also want to check pump fuse, but can't find which one. This is an 04 with 84K mi.

 

Patrick, I just finished replacing my pump and all is fine. Following your instructions made it almost easy and enjoyable. It looks like the system might bleed itself just running the pump,but I did use bleed valve. Your instructions were detailed and complete, just what I need. I can tell you are truely an expert. Thank you very much, Gene

 

Hi All,

This forum has been a great help to me so a quick thanks to all the people that contribute to it.

I am getting ready to order the new inverter coolant pump part #G9020-47031 I am just wanting to make sure this is the newest version of this pump. Did it just have the one revision? Anyone know what got changed and now long the new one is supposed to last?

My old one is still working (car has just over 120k) We have not had it since new so I do not know if it has ever been changed. I figure I want to at least have a new one on hand and maybe go ahead and just change it so I don't have to worry about it.

 

Hi Chazz--
I just replaced my inverter coolant pump last weekend at 101k miles and the part number was #G9020-47031, just as you listed. (I replaced the pump just as a precaution.) I think this part # is the newest version, based on the listings that I checked out at a couple of online vendors. I found the lowest price online at Conicelli Partznet:

G9020 47031, W/pump - Inverter - Inverter $85.91

The new pump is much quieter than the old one was.
I removed the headlight and this made the job much easier than going in through the top -- I'd do it this way again.
Good luck!

 

I will consider changing this on my 05 I just got however was there a recall or something on this part and how do I know if it has been replaced previously? update just saw the pump on my car looks like should be pretty simple to replace not too bad as far as clearance. I did notice some slight leakage around the hose but not bad for 80K a lot of dust as well. The main water pump looks a bit more difficult and I am shocked on the size of the serp belt! That is the smallest belt I have ever seen on a car.

 

My pump is making a intermittent "squawking" noise when I first turn the Prius on or off. I thought this was a pump for the "Thermos bottle"? It's been doing it a while, worse during cold weather. Is this the Inverter pump?

Thanks, Greg

 

I think it's the coolant heat recovery system pump, it only comes on during start up and after the car is shutdown. I hear the brake pump come on sometimes, but it has a different sound. The pump seems to work ok, no warning lights, just the noise from time to time, sounds like a bearing is going out. It's worse when the weather is colder. I guess it will fail eventually so I would like to change it, do you know how hard it it to get to? I had stopped by the dealer and they said it was the inverter pump (which I have my doubts) and it would cost $433 to replace.

I just downloaded the manuals, I'm not sure where that pump is located in the manuals.

Thanks, Greg

 

Patrick, it may be useless in CA or AZ but here in NY winter, it improves the MPG and cut down the cold start emission.