Cleaning the Prius Hybrid Fan for Preventative Maintenence

Cleaning it is nothing. Most small fans die because of lack of lubrication. Lube it like any other dc fan. Peel the label off the back bearing and squirt some oil in it.
3M makes oil for just this application. Lowes sells it. 3M oil for electric motors. I used it on the fan on my ac compressor too.

If that fan dies you will never know it.

 

mostly beard hair from a cab driver or did it suck in a ferret?

 

Quick bit of troubleshooting for any future folks who run into this. If you forget to reattach the fan electrical connection you will get these error codes;
p3191, P0aOf and the red triangle and other lights. The engine also seems to run very roughly on start.

Hope this helps someone else and speeds your troubleshooting!

 

Why don't you just use mass airflow cleaner? It doesn't leave a residue when it dries and is made for more sensitive electronic parts. The only downside is it's like $10 and it uses a lot to clean it, but it sure beats trying to scrub with a toothbrush or cotton swab. This job is super easy if you've ever done anything with trim or a 10 mm bolt before. The battery is really expensive and vital and it needs a well functioning fan. I did mine at 120k and it was reasonably dirty. It might have been done before. My plan is to do it at least every 50k.

 

I found cotton swab worked quite well, perfect fit for the spacing of the fins. MAF cleaner is for critical electronics, overkill. It’s just dust, comes off easy. You can clean it without complete removal too.

 

This smells a lot like assuming two things are related because they happened close in time. P3191 is about the engine running very roughly on start, and P0A0F is because of the P3191, so no surprises there, but it all points to an engine issue that happened to exist and go away around the time of doing things with the fan connection. The operation of the battery cooling fan is independent of the operation of the engine.

 

If he's talking about this connector being unhooked then yes it will definitely cause problems. For some reason the fuel pump wires go through this connector. I can't remember if it the hot, ground, or both. Either way the engine won't run if unhooked. I see a lot of nasty corrosion in that connector so a lot of times we just cut it out and solder/heat shrink the wires together to avoid any issues later on.

 

*head explodes* ah, I see it. That 13-pole connector (with only four used) isn't officially "the fan electrical connection", it is listed (BM1) under "Connector Joining Wire Harness and Wire Harness". It is where the "Floor Wire" (which runs down the left side of the car and connects to a bunch of stuff) and the "Floor No. 2 Wire" (which runs down the right side of the car and connects to a bunch of stuff) connect to each other.

So the fuel pump power comes from the C/OPN relay (on the engine wire harness) and into the floor wire (left side) at the left kick panel, but the fuel pump connector is part of the floor no. 2 wire, so it connects across at BM1.

Likewise, the Battery ECU (where the fan control signals come from) plugs into the floor wire, but the fan relay, motor controller, and motor all plug into the floor no. 2 wire (and the power to the relay comes along the floor no. 2 wire from the right kick panel).

And those are the only circuits that jump between floor wire and floor no. 2 wire like that. So yes, if you unplug connector BM1 between those two harnesses, there'll be no fuel pump, and P3191 ensues.

I have learned my new thing for the day.

 

Same here!

On the cleaning aspect, the slickest way I've found so far for cleaning the fan is to first blow out the big chunks as most do and then use a spray bottle with Simple Green. It just flushes the residue right off the fins. Then rinse with water. Looks like new.