gen 3 hybrid battery cooling fan dust buildup

I wanted to log my results from a blower fan cleaning/inspection at 90,000 miles. A lot of those miles were transporting a dog who is very prone to shedding year-round; she sat in the rear right passenger seat which is right by the fan inlet. Resurrecting an old thread here but it's the most relevant resource for this post.

In summary, I was anticipating a rat's nest inside the blower fan because there is dog hair all over the interior of our car. In reality, the fan was entirely free from fur and only had a very minimal amount of visible dust. Ultimately I didn't take any measure to clean the fan as I felt it was in almost-new condition.

Getting to the fan was much easier than I anticipated. I'd read in this and other threads that it's about an hour job to disassemble and 15-30 minutes to put everything back together. It took me 45 minutes start to finish and this included a lot of time spent searching for tools. I skipped a lot of the factory service manual disassembly steps because they were unnecessary for fan inspection and probably for cleaning as well. I will document my steps below (sadly I didn't take any pictures).

Relevant Toyota Service Manual PDF here: https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/priusdisman3rd.pdf

Please read the above PDF. It has a lot of important safety info that you need to know before proceeding.

1. Remove center deck board.
2. Remove center auxiliary box and battery cover and disconnect negative terminal from 12v battery.
3. Remove service plug grip.
4. Follow safety steps indicated in PDF above.
5. Remove the Nos. 1 and 2 floor board sub-assemblies.
6. Remove the No. 1 floor board.
7. Remove the rear floor board spacer.
[NOTE: at this point you should be able to see battery cooling blower assembly and hybrid battery intake duct].
8. Remove the clip that fastens the blower assembly to the intake duct.

At this point you should be able to pull the intake duct away from the blower assembly and see inside the fan.

Reverse steps to put everything back together. Ultimately there were some clips that weren't easy to fasten which I just left unconnected; others have reported the same.

Once everything is put back together you will have to start the car three or 4 times before you clear the "HV system check" warnings at startup.

 

I didn't disconnect either the 12 volt or hybrid battery safety plug. Maybe fool hardy? Or maybe Toyota's lawyers had a hand in the instruction?

 

I pulled the plug but didn't touch the 12v. just didn't feel comfortable starting a post with "you can skip most of the steps" and then gloss by the safety stuff.

 

weird, how come some people have huge problem with this yet you (with your dog) didn't?
i'm thinking i'll delay mine till 100-120,000 miles. (1-2 people, 0 dogs riding 95+% of the time).

 

Thanks for the post I did some more digging and the 2013 has a inside filter right behind the inlet vent with the part number G92DH-47060, it won't hurt to put a cut vent filter between also and replace every 6-8 months with just one bolt to open and install.

 

For one, I would guess that only 25-30% of miles were done with dog in car. maybe those with big problems had many more miles with dogs and/or kids in the back. we didn't have a family until about 2 years ago and rarely use(d) the back seat even still (our primary car is not the prius).

But this dog sheds a lot - we can't keep our house clean and the grey prius interior is covered in her red/blonde fur everywhere. we used to try keeping things fur-free but it wasn't possible so we just stopped trying. i was expecting a nightmare at 60k and thought i'd have hell to pay for waiting til 90.

 

Considering it's not that hard to get to the fan (once you pry off the myriad of %$#@&! fasteners), I'd much rather find I'd done it too soon, than too late.

 

Toyota posted a TSB-0098-12 to cover this problem for 2010"s in 2012 under a 96 mo. 100k warranty (120-150K for CARB) they cleaned out the fan and put those filter adapter thingys on vent. @2Hrs. labor+ . They extended to 2013 severe use vehicles...pretty dirty fans out there...clean it out! a P0A80 replace hybrid battery could appear on MIL..that is scary stuff.
and yes, disconnect 12V ground before working in any electrical component.
I think I will just improvise a filter inside vent or clean again in say 100k.
Bloo-dog doesnt ride in prius anyway...He rides in the Previa.
no battery cooling fan there!

 

I've never disconnected 12 volt battery to clean the fan, seems like overkill.

 

Especially since you disconnect the fan prior to removing it and before you really get into any serious disassembly.

But I guess you could always stick your hand where it doesn't belong.

 

i knew that line would bring out the best tech's ...but its just old school

 

I cleaned the fan without removal. I suppose it would be prudent to disconnect its power lead, I didn't think to do it though. Yeah next time.

Still, I would think the odds of that fan starting up with the car off are pretty much infinite. And it's a small squirrel cage style fan, I'm just reaching in with Q-tips, dusting the closely spaced plastic blades, then hitting it with some air.

 

I don't have any pets and my youngest child is 13, but when I saw someone mention hearing their fan making a lot of noise and finding a candy wrapper in the fan, I bought one of those covers (on ebay). Cheap insurance.

 

Bump. Just wanted to share my experience with the HV battery fan for those that might be in a similar situation.

I am the proud owner of both a Siberian Husky and a 2010 Prius with 68,000 miles. I frequently transport my dog in the back seat and, as anybody with a husky will tell you, they pretty much shed year round. I try to keep the dog brushed and the car clean and vacuumed out, but the vehicle had been acting weird for the last several months and made me suspect there was an issue with the battery fan. For example, I would frequently hear the battery fan (sounds like a hairdryer in the back seat) during normal drives even though I never really heard it before. In addition, the ICE would continue to idle when the vehicle was stopped or at low speeds despite a near-full battery on the HSI. I could almost never put the vehicle into EV mode, even after it had plenty of time to warm up, and would just get the 'EV mode not available' message. Finally, my gas mileage was significantly reduced, as I couldn't seem to get a gas mileage above 40-42 even though I used to get about 48 easily without changing my driving habits.

Because of the way I use my car and the symptoms I was experiencing, I decided to take a look at the battery fan yesterday. I read through this thread a bit but finally found an awesome YouTube video posted by NutsAboutBolts that walks you through the process step by step; here's the link:

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The only thing I did differently from what he did in the video is that I did not remove the back seats. If you just push inward and down on the edge of the rear passenger side seat bench that's under the battery fan cover, you can use a socket wrench with extender to access the bolt to remove the fan cover without having to take off the seat bench. I also didn't worry about pulling the service plug or disconnecting the starter battery, although I did make sure the front cabin lights and trunk area light were off so as not to run down the starter battery while I was working on the vehicle.

Lo and behold, once I got down to the fan and I removed it, I discovered that it was full of husky hair! (pics attached below) Once I vacuumed out the hair and put everything back together, I took the car for a drive and didn't hear the battery fan at all. Also, I got 45 mpg without really trying and the ICE was no longer idling with a full battery.

I'm glad I discovered this when I did, because it is obviously pretty bad for the traction battery. I do find it strange that I never saw any warning lights or error messages, especially given that the problem was enough to cause a noticeable decrease in MPG and a change in vehicle behavior. In summary, I would highly suggest that anybody who often has pets in the car do this maintenance if they notice a decrease in vehicle performance. Might go order that HV battery fan cover now!

 

Yeah, same here: dug down to ours a day or two back. NO nead to remove rear seat, just push down the seat, sneak a socket extension in there. Ditto for battery service plug, I survived.

We have a Shiba, just very occasionally goes with us. It'd been a year or two since my last check; the fan was still so clean I didn't bother to do anything.

Only 67K kilometers on ours.

Public Service Announcement: check your spare tire pressure while you're at it.

 

I am debating trying the cleaning of the fan on my 2010 prius. I bought it used with 93000 miles on it and have no idea if the current owners had pets, etc...
Only issue is that to me the process of getting to the fan looks like tearing the whole back of the car apart.
Is it really worth doing if you have no codes on the car or no indication of a problem. I would hate to tear something up getting to the fan just to find its clean

 

It's not that hard. There's a video here, pinned at the top of the maintenance sub-forum (by member @NutzAboutBolts), on how to access the fan. I've done it a couple of times, a few comments:

1. Contrary to the video, you really don't need to pull out the rear seat bottom. Just push down on the rear seat cushion, on passenger side, and reach in a long extension on ratchet wrench (12mm I think) and remove a single bolt. Be careful not to drop it.

2. The hatch floor section over the battery needs to be pried off. It has a number of tough push-in fasteners. Use a pry tool and go carefully. FWIW I left them all off when I re-installed the floor and it's still very secure, doesn't rattle. Makes it much easier for next time.

3. Once that (comment #1) bolt is removed, you tilt the seat back forward partially, then just work the corner piece of the seat back (with the fan opening grill) up and out.

From there on it's pretty much follow-your-nose, nothing too complicated, one or two small bolts, and some relatively easy push-in style fasteners. The object is to get down to the fan; it's not necessary to completely remove it. just pulling off the ductwork (and dusting it out), you can reach into the fan, run Q-Tips through the blades, vacuum and blow the dust out.

 

I would recommend doing it. I bought my 2010 with 90,000 miles on it and no maintenance records. It wasn't hard to do - it took me about an hour. My fan was dirty and it probably would have been fine, but I wanted peace of mind. I also bought one of the grilles to put on the inlet.

 

I click the Post Reply button and it acts like it never does it, so I click it again and it acts like it never does it, so I press Refresh on my browser and there's two posts from me! Why?!? Ugh.... I don't see an option to delete, so I edited this one.

And now the same thing is happening with the Save Changes button. I'm betting this will be a double post when I click the Save Changes button for the second time....

 

I would recommend doing it. I bought my 2010 with 90,000 miles on it and no maintenance records. It wasn't hard to do - it took me about an hour. My fan was dirty and it probably would have been fine, but I wanted peace of mind. I also bought one of the grilles to put on the inlet.