How to Replace the Inverter Coolant Pump

Just to bring this thread back to life...

Yesterday I experienced the warming lights that some say point to the inverter coolant pump problem
brake (!) VSC ABS

And while I haven't solved the problems, or gotten the warming lights off, I've learned a couple of things:

1. My inverter coolant pump seems to be working just fine (sound and turbulence in tank)
2. My 2006 VIN is younger than the change-over to the better pump.

I never saw a notice from Toyota. I suppose I should call them up and see what's up with that... and have them determine the cause of my error lights, since I can't find anything wrong, and can't clear them!

If I understand, Toyota is doing this replacement on the affected cars at no charge now?

 

Yep.

Can you pull DTC error codes ?

 

Thanks Sage. Nope, I can't pull the codes. I can (and did) read the flashing codes from the lights, and got:

45 VSC
42 ABS
49 (!)

Patrick says the first two codes are not listed, and the last one suggests brake light problem - the brake lights work perfectly. Go figure.

I've tried to clear the codes by pressing the brake pedal 8x with the OBD2 jumper in place, but no dice. I'm not sure when to remove the jumper (still ready-on, or after ready-off - I've only tried after ready-off, and the warming lights are still on.)

NEW INFO: Pull the jumper while still read-on. Worked for me!

 

OK... some good news. I managed to clear the error lights by pulling the jumper while the car was still in ready mode after pressing the brake 8x in 5 seconds. (I was turning off the car before pulling the jumper out.)

Sequence: Jumper in place (4, 13), car to ready, press brake 8x in 5 seconds, pull jumper. Lights are cleared.

Now... I just turned up a code reader and I'm going to see if there's anything exciting to report.

update: Code reader claims NO codes. I was wondering if clearing the lights also cleared any stored codes. It appears that's possibly the case.

 

OK, so I'm finally home safe and sound... drove over 100 miles with all the lights back on (they came on after a few miles of driving, and stayed on. NO issues beyond the lights. But here's the thing - I believe I now know what happened, though not the extent of the damage - While poking around trying to find anything odd, I found a rat's nest down below the coolant pump! Shredded plastic bags, leaves, fur... poop. And several wires with the insulation completely chewed off. Couldn't see it with ambient light, but a flashlight told the whole story. I taped up all the wires I could find for the drive home - and like I said, no issues on the drive home. Next week we assess the damage when I've got some time....

 

Ouch. Sorry to hear the cause, but thanks for posting follow-up Darell.
Good luck with the repair.

There is one silver lining to this though: you have another bit of ammo against gassers. They attract rats!

 

The car is at the dealer. I want to make sure the cause of the lights is found. I'm NOT sure if I want to pay them for the simple task of repairing wiring harnesses, but the first step is to determine exactly what's going on.

One interesting note: If started cold, the lights stay off for a couple of minutes of driving before coming on. If restarted warm, the lights come on immediately.

Oh, and one final note - I already have the new inverter coolant pump! They replaced it when they did my "your Prius will kill you unless we shorten your gas pedal" campaign back in Jan of this year. I had no idea... he showed me all the paperwork, and sure enough! I thought the bracket looked way too shiny to be a few years old!

 

It would appear that this is the wrong thread to discuss this in now, for sure. The dealer just called. The problem is some issue with a switch in the brake system. The brakes work just fine, but the switch isn't responding correctly. $318 later, I'll have a car that works the same, but doesn't light the scary error lights.

 

And so... Is there any means to detect or to give you indications as to when this notorius inverter pump would quit working? I've got an 05 with 117k miles and still working (knock on woods). Also, I live in washington state where we dont have tripple digits on peak summer.

 

Hey, I just want to say a great big Thank You to Patrick Wong and all who were in on the discussion on this thread. Thanks to reading this, I was able to determine that my P0A93 Inverter Cooling System Performance was being triggered by a failed pump. Picked up a pump & a gallon of Toyota SLLC at my local dealer (didn't have the time to wait for a better price on eBay ), and installed in a little over an hour.

Have visible turbulence in the inverter coolant reservoir now, whereas I didn't before. It's been 2 weeks now and the code & all the warning lights have not reoccurred. (Worth noting that the brake warning light was among those being triggered. I deduced that it was triggered because of a voltage drop which was occurring while the inverter was getting too warm. It has not reoccurred, either.)

Looking forward to participating in Priuschat -- this is my first post. Thanks again!

 

Yes, I read about the LSC, and it did occur to me to contact Toyota. I bought it used in Houston, TX less than a month ago with 103K miles on it (anything with around 100K on it is like a new car to me!). It is in super-clean shape except for a couple of dings that I am taking care of soon. I was driving it home to Mobile after the purchase when, at 11 pm at night, during a very dark stretch of I-10 between Beaumont and Orange, TX, it suddenly dropped out of cruise and the dashboard lit up like a Christmas tree with all those warning lights. Having that sinking feeling in my stomach about my purchase now, I pulled off at a rest stop, looked under the hood for anything obvious, but saw nothing. The performance seemed OK. It had oil and coolant and didn't appear to me at the time to be overheating. I left it off for about 30 mins to see what would happen. It started back up with no warning lights, so I thought maybe just an ECM hiccup. Drove on for 30 or 40 mins or so, then it happened all over again. I kept shutting it down & restarting like that for 3 or 4 similar cycles, then finally gave up and just let the lights stay on while I drove on home (with no cruise control). The trouble lights stayed on continuous after that for the next couple of days, but performance seemed fine. So, I drove it to work for a week (184 mile r/t commute!). The lights went off and stayed off after that first couple of days, then reoccurred after a week. Had the code scanned at Autozone and got that P0A93, Googled it and found this site/thread. Lucky I hadn't fried an inverter, I guess. Car really seems fine now. I checked and I'm getting a solid 13.8 volts when it's on. Probably a good thing this all happened during winter and not during middle of the hot summers we have here in the deep South.

I will say I was impressed with the Toyota SLLC. I drained it for the repair and the stuff looked as fresh as if it had just been poured from a new container. I don't know if it had been flushed & refilled before, but the system looked clean as a whistle with no scale, gel, or gumminess, etc., as far as I could see. I would normally be the type to just grab what I could get from the local parts store, but I was so impressed I took your advice and plopped down the $24 at the dealer for a gal of the SLLC, and kept it "pure". Note: Guy at the dealership parts counter told me there was no difference in the LLC & SLLC, that their own service guys just poured in whichever they had handy. Maybe, but I didn't go for it.

No more troubles since the pump replacement, and at least I didn't have to pay $375 to the "stealership". Enjoying driving to work & back now on less than 4 gals!

 

Hi guys. im new here but i have a question. my 2005 prius will not turn on. it goes to the first screen where the dash lights up and the radio can play and all but i can only go to neutral. the check engine light is on and the master warning light as well. i diagnosed the problem with the code reader and got 3 codes. the first 2 are identical

P2601
coolant pump control
circuit
range/performance

U0293
lost communication
hybrid power train module
control module

I can see the coolant pump wasnt working. because there was no movement in the coolant reservoir.
this first code showed up about 5 months ago and i just ignored it until now.

2 weeks ago i went in to toyota to change the water pump through a recall. next day the dash lit up like a dash board. and after i turned off the car i cant get it to start again until i reset the codes. PLEASE HELP ME

 

In the engine compartment, check the AM2 fuse in the fuse box, mine blew when my inverter pump quit. Believe it to be 15 amp, there is a spare in the fuse box you can use if needed. Your last statement is confusing to me, the pump was replaced, and now you have problems? Anyway let use know if this fuse, or another one in the engine fuse box, is blown.
If the replacement fuse also blows , try disconnecting the inverter pump and try another fuse of the same amperage. I was able to drive my car when my inverter pump fried for the second time about a month ago. (I then went in for the inverter pump recall, car is drivable, to some degree, in cool weather). You probably also need to go back to the dealership to get their inverter pump fixed correctly

 

So I have an issue that clearly nobody has been dumb enough to do yet, since i haven't found an answer anywhere...

So my inverter pump went out and thinking I could do it myself I attempted a replacement. Before I received the part, I thought i'd save time by pulling the old pump out.

Well, I drained the coolant, started disconnecting hoses and pulled out what I thought was the inverter pump. Well, when I got it out it looks nothing like the picture everyone else shows. This part has 3 hoses attached to it and (now that i realize where the real inverter pump is) it is actually housed slightly to the left of the inverter pump. I believe it is part of the same coolant line because I could see the pink coolant draining out but now i'm really confused.

1) what part is this?
2) i'm assuming i can just reconnect the hoses and take out the real inverter pump for replacement?

I can't believe i wasted an hour pulling out the wrong pump!

 

this is not the water pump correct? this is the coolant one?