How to Replace the Inverter Coolant Pump

great reveiw. May 2021, 2004 pri 182k.
we are changing pump again after just 3 years. in NJ its hot but not that hot...
could there be another reason why pump failed... ?
Are there other temp sensors etc we should check?

A week before the only thing i did was clean the headlamp near the pump which involved electric sanding and spray acrylic....

All fluids were changed by dealer last year... thx for enthusiasm

 

Patrick
Thanks my guru of Prius. This spring have replaced the traction battery @ 115K on my wife's 2006 Prius. Also the Die Hard is new in June. Traction battery replacement Work was performed by Green Man Battery out of Raleigh NC. Unfortunately the Inverter Pump was not replaced under Toyota recall and I'm suspecting the car may have also been in a front ender and may have had the fans removed and replaced in reverse. Thus your comment about this disrupting the cooling flow to the engine and inverter.
Question 1 : How do I determine the fans are installed properly.? do they suck or blow into the underhood area
Question 2.: My OBD2 handheld is old and doesn't give me Prius Hybrid info or codes. It does seem however to clear codes and resets the triangle of death/brake/check engine/vsc dash lights and does reset the dash ready light. I need to provide hybrid codes to green man so they will know whether or not to come out replace my Refurbished Traction battery.
Question 3: Please recommend a cheap but functional Prius Hybrid OBD handheld so I can move on and any other ideas which you might discern.
Many thanks in advance.
Dave Mclintock

 

Question 1: they definitely pull air from in front of the car, in through the grille, through the condenser, through the radiator, past the fans, and into the engine bay. Or they darned well should, anyway.

It does seem to be easy to mess them up on reassembly, by not noticing which way they rotate and which blade goes where. It's funny, a thread on the same topic but for Gen 3 has been active just today. That gives the Gen 3 details.

I am not positive of the details for Gen 2, but from the diagram they appear to be the same, right down to the two fans having different blade counts.

 

You’d think the engineers would have the presence of mind to ensure they can’t be mixed up? Say the fans swapped or flipped. Maybe not so much?

 

I'm not completely sure that isn't the reason they have different blade counts: so you can tell they're different, and see which goes where right in the diagram.

 

Replaced my last pump at a private shop. Dont remember what they charged but I dont believe it was too bad.

After 40k miles, it went out so I decided to do it myself.

I bought a used OEM and it took about 1.5 hours for install by going through the headlight. (Could probably do in an hour)

Hardest thing was working in the mid-day sun.

Barely lost coolant (blocked bottom hose first) and also used a 1/4" inner diameter hose to bleed the system too.

I highly recommend everyone DIY this when its your time to replace.

 

Thanks for this DIY post @Patrick Wong
I experienced my first dashboard light-up this warm afternoon @ 70mph on the way to get some Costco gas w/ my son in the back in my Mom's 2008 w 147k

The code reader I have in the glovebox couldn't read the code, but the Amazon RPM OBDII Gauge I had from my old Turd Gen could read the code, the P0A93..with this being one of the most relevant posts.

I just ordered my G9020-47031 from Fred Anderson Online for $90 and will aim to pick it up locally, and get this done sometime later this week

 

Thank you Patrick for the detailed instructions. Here are a few photos of the inverter water pump that I removed after a my pump failed a few weekends back. I wanted to know what made it tick so I tore it apart and it appears to be a electronic control board and a magnetic turbine pump wheel which that creates the coolant motion. In my cause I lost movement in the reservoir tank, got the triangle of death etc so I purchase a new OEM part from Toyota. Also, the photos show a genuine Toyota part that was replaced under recall which failed at a guesstimate of 8 years later. The inverter pump seems to be thermally sealed plastic with no serviceable parts so I cut it open. In my cause the pump turbine still spun freely but my guess is that something on the electronic control boar which is built and sealed into the base of the pump failed. Just my guess and I could be wrong.

 

Aisin SLLC from Rockauto $14/gal. Shipping is $8.99 if you buy 2.

Aisin Aftermarket

AISIN Seiki Co. Ltd., was founded in 1965 as an OE manufacturer. Approximately 24% of its ownership is retained by Toyota today

 

Yep. Flip a coin. Heads - something on the circuit board fails open so the pump stops and you get a P0A93 overheat code. Tails - something on the board shorts and blows the AM2 fuse which kills the car.

Just happen to have a 08 come in late Friday- dead pump and P0A93. Pump's on order for Monday.

Posted via the PriusChat mobile app.

 

When bleeding the inverter....is the car on or off? Instructions seem to say the car should be off?

 

Does it matter, so long as the pump is running?

I did this job a few months ago and I didn't lose much coolant so I didn't do any formal bleeding procedure.

 

It does help to know the names of the different modes the car can be in, so posts in a public forum won't be confusing.

The car can be in OFF, ACC, ON, or READY. The pump will not run in OFF or ACC. So that leaves ON or READY. The manual suggests ON, not READY, so you can get all the air out of the inverter cooling loop before you start asking the inverter to do stuff.

 

on is activated by pressing the button twice without pressing the gas pedal?

 

Yes.

Gen3 modes: Ready, Limp, Maintenance, etc. | PriusChat

 

So i got it done...took around 1.5 hours. One thing which concerned me was that even after tightening the 3 bolts on the pump body...there is still a bit of wiggle room. Is this normal? Basically the pump body can move around a bit and there was no way to snug it down (actually broke one of the bolts trying to do this lol)....

Any ideas?

 

The pump vibrates. The mountings are rubber and loose enough on the bracket to avoid transmitting the vibration into the body of the car. When you tighten the bolts down, they tighten only on the bushings inside the rubber mounts. That's all by design.

You'd be surprised how much difference that makes to the sound. I picked up a rebuilt Prius once where the pump had been attached so tightly the rubber mounts couldn't do their job, and sitting in the cabin sounded like being trapped in some industrial machine. All because of that little pump, but with its sound carried straight into the body steel.