As a Prius owner, I have learned a lot about how to troubleshoot any issues that might arise. Luckily, I'm willing to share my findings!
Why Clean the Battery Fan?
The battery-cooling fan does its job hidden behind the interior trim panels in the rear cargo space of the Prius. Toyota doesn't require or suggest cleaning this fan as part of a regular maintenance schedule, and most people won't ever need to. However, if you regularly carry furry friends in the back seat, you might want to do so every 60,000 miles or sooner.
The cooling fan intake vent—in the rear-right of the Prius—can suck in loose hair and debris, clogging the fins inside the blower fan that feeds cabin air into the battery pack to keep it cool. If allowed to accumulate, over time, the fan will eventually be completely clogged, preventing the fan from cooling the battery effectively. This can produce error codes related to the battery pack overheating, reduce performance—the multiple ECUs (electronic control units) will limit battery usage for driving or regenerative braking—and lead to premature failure from being subjected to extreme temperatures.
Tools You Will Need
To access the cooling fan, you will need the following tools to remove the interior pieces and components:
- 10 mm socket
- 12 mm socket
- A pair of good hands
I also recommend an upholstery pin removal tool that slides under the head of the push pin. It allows you to pop it out much more easily than trying to pull on the material around it.
Step-by-Step Directions for Removing the Battery-Cooling Fan
1. Remove the rear seat cushion at the back.
2. Remove the bolt and pull out the intake grill assembly.
3. Fold the seats down.
4. Remove the first bolt securing the right rear trim panel.
5. Remove the second bolt securing the the right rear trim panel.
6. Remove the third bolt and luggage strap hook.
7. Remove this part of the hatch trim.
8. Remove the left luggage hook point.
9. Remove the right luggage hook point.
10. Pull up the carpet panel covering the battery.
11. Remove the push pins at the bottom of the right rear interior panel.
12. Pull the right rear trim panel out.
13. Remove the intake duct.
14. Remove the three 10 mm bolts securing the cooling fan.
15. Detach the fan's control plug (but don't disconnect).
16. Remove the fan's power plug.
17. Clean the Cooling Fan
If the fan has hair or lint in it, try using a vacuum cleaner with a crevice tool to suck it out. For finer, stickier grime that won't vacuum off easily, use an old toothbrush or pipe cleaner to loosen and then vacuum it out.
When re-assembling, make sure you get the power plug for the fan reconnected before bolting everything back in or else your Prius will throw a diagnostic trouble code related to the battery cooling fan not working (well duh) and a master warning triangle light on the dash. This won't harm your Prius—it's just letting you know something isn't right.
The code can be cleared by disconnecting the negative terminal on the car battery for a few seconds before reconnecting. Keep in mind that if you need to do this, you'll lose any radio presets as well as mileage driven and average MPG information. You will also have to re-initialize the auto roll down feature on the driver window. Hold the control button down until the window is fully down and then hold it up until the window is all the way up.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2013 Jeremiah Simpkins
Clay Wells on June 04, 2019:
Thank you again for the great information!
Jeremiah Simpkins (author) from Pulaski, VA on September 02, 2017:
Hey Brian! Glad to hear it helped!
Brian on September 02, 2017:
Just wanted to give a shout out for this article. My dog kept throwing hair at our battery fan and it finally let us know.
Followed the instructions, problem solved. Thank you!