I took some photos to show how the TCH air filter housing is removed. It is mostly straight forward, with the exception of a cable support fastener that needs removing by compressing it's fins.
A 9mm socket removes the two bolts on the drivers side of the housing (red arrows) and bolt to loosen the hose clamp on the other side (red arrow.) The electrical connector easily disconnects with a gentle squeezing (top and bottom squeeze to release) as you pull it out (blue arrow.)
The only tricky part is releasing the electrical harness support fastener without damaging it (blue arrow.) I didn't want to cut the support from the cable to free it. I found that a 7mm socket almost compresses the fins enough for it to pop free. I used a 6mm to pop it free the rest of the way. What is really needed is a 6.5mm. I may drill out a cheap 6mm socket to make my own removal tool.
Here is a photo showing the cover removed, and the plug and fastener disconnected.
Good DYI. I wonder why there's an electrical connection to the air filter? Do you know if you are required to buy an OEM air filter or if there is an aftermarket one available? I wonder how much the OEM filter is?
Yes, it is indeed the "Mass Air Flow Meter" that connects to the wiring harness. Toyota uses this instead of a "Manifold Absolute Pressure (MAP)" gauge. Inside the top half of the air cleaner cover is a maintenance-free carbon filter (not shown in the pictures).
P.S. nash, if you give the aircleaner a good horizontal "whack," do you get a rattle from something inside yours? Please let me know! Thanks.
nash — Thanks! I'll have to investigate further to find the cause of my rattle. It might be the Mass Air Flow Meter, as there doesn't seem to be anything to rattle in the bottom half of the case. [I had already opened my air cleaner up in the hope that there was some obvious source for the rattle, but couldn't see one. I'll need to get the top half off the car in order to test whether the rattle is indeed in the top half.]
Today I installed my TRD filter. I found that a 10mm socket was needed for the bolts and I have no luck getting the support clip off. In fact, the entire piece broke off the air box! Oh well...
Anyhow, I can see the edge of the TRD filter on the "hinged" side. I tried to get it to completely cover it but couldn't. Has anyone has a similar issue after changing the filter? Does anyone thing this would be a problem?
Also, I notices there was quite a bit of dirt and water spots in the air box under the filter. This doesn't surprise me seeing as I am always wiping dirt out of the duct. I think they should have protected it a little more.
Lastly, what's the deal with the upper air filter? Do they not think one is enough????