Cojones

How to check if my active air intake flaps on my 991.2 is working?

NY9112

Turn the car on and see if they close.

Basically they are open when parked, closed at low speeds or temps (can’t remember which), and then open back up as speed/temps increase. Just leave it in normal mode as I think Sport+ might keep them open always.

Fwiw they are totally superfluous. Think they help Porsche improve efficiency specs on paper, but I have the motor disconnected on mine so they stay open (have laser jammers in pods above the top slat) and have no problems.

VII7

Nvm

asellus

I'm reasonably sure it will throw a fault if they aren't, or at least if the motors aren't running and giving a readout of their position. @NY9112 do/did you get a fault with yours unplugged? It's controlled via the front body module, if I'm not mistaken, so there ought to be a bit of CAN-y communication happening there.

My Autel unit can do active tests of them, actuating the servos. Just did this no more than a week ago, and I vaguely recall there being a readout of % actuation in the diagnostic. Any bidirectional diagnostic tool should be able to perform this test. I'm unaware of any way to force them to open/close without a tool, though.

As mentioned, they are open when parked, and they close under specific circumstances -- the nebulous explanation by Porsche is they close "when the thermal load isn't high" -- which translates vaguely to "when it's cool out and you're going between 15 and 35 mph" and other various specific scenarios.

If they're open right now, you really don't have anything to worry about.

NY9112

I don’t get any codes thrown while driving, but if you scan it there is a code for some sensor. Forgot the exact wording on it. It’s not like “active intake fail” but something like “air temp sensor fail.”

The key is you physically disconnect the servos from the flaps rather than cut them and then once they are disconnected you have to put something behind the flaps to keep them open or they will just fall shut. If you turn your key and stand outside the car you can hear the servos going, which is probably what keeps you from getting a more significant code.

Musicar sells a part to keep them propped open (if that’s what you’re looking to do) and can walk you through anything I might be missing. Had my installer do it when he put in laser pods so not sure if anything else you need to look out for if trying to disable them to always be open.

asellus

Oh, that makes sense. You still have the servos plugged in, so the car is none the wiser. I've never heard the servos actuating when I initially turn on the car but I suppose I've never paid attention. I'll go try that in a little bit here!

asellus

Hmm, doesn't look like ignition-on actuates them. It would make sense to, to ensure they are functioning, but alas... mine do not. They definitely work though.

911.

I completely removed mine and added a custom mesh. I left the motors plugged cause I wasnt sure if I would get error codes. Good to hear that it doesnt.

Cojones

It's fine at the moment But I was just curious how would one know if it was functioning or not, other than visually have someone follow look externally. Thanks!

Wujohn

I removed mine and they were fine for roughly two years and now I am throwing a code (not always on) with a yellow warning. I need to pull my bumper off; assume that a connection is loose or something. Previously when I brought it into the dealer (pre warning light) they told me there was a hidden code it threw. Don't recall what the code was though.

Cojones

Does the mesh get in the way of the slats opening and closing?

Wujohn

There are commercial options available that sit on the inside of the slats and do not interfere. There are others that sit on the outside. I personally did not like the louvers at all, so I removed them.

Valvefloat991

I don't know that they are superfluous. They reduce drag and improve fuel economy at highway speeds by a small amount. You might consider than superfluous, but that doesn't mean it isn't happening. It's one 0f the reasons that a base Carrera gets 32 mpg at a true 80 mph.

Also, as you start driving harder, not only do the flaps open, but the fan motors also turn on to keep the engine cool. In fact, the S and GTS models have more powerful fan motors than the base Carrera for this purpose.

Pavegeno928

My old 1988 928 had active flaps. Closed to help the engine get up to temperature faster to aid in emissions. Opened when the liquid cooling thermostat for the radiator opened or anytime the air conditioning was switched on. Worked great and never had a problem with it on the 928.

DaveGee

Further proof that everything old is new again.

DaveGee