Help! HVAC blowing intermittently - 2012 Cayenne Base

[lesgrossman]

Dear Enthusiasts,

 

My 2012 Cayenne V6 base model starting blowing air intermittently shortly after a regular oil change. It would blow at startup and slowly taper-off at exactly 1 minute. Then it would stay off for about 10 minutes and blow for another minute. I could not find anything on the web for my particular year/model. Please advise and thanks in advance.

 

-bazza

[deilenberger]

Dear bazza,

 

This would require a Porsche specific code reader (Durametric, ICarScan) to diagnose. A WAG is the controller for the HVAC - but that's an expensive part to replace on a guess. It could also possibly be a failing switch.

 

Do both sides do the same thing? Or only one side?

 

With a code reader one could read the inputs from the switches into the module, and then read the output status going to the fan. And the stepper motor positions for the vents. At least with ICarScan I can. I haven't hooked up my Durametric to see if that's possible (mostly just from sheer laziness - it's way too easy to use the ICarScan.)

 

So it's either buy a scan tool or visit the dealer time IMHO. I'm sure the HVAC module has to be coded to the vehicle, so no real avoiding that.

 

Good luck and let us know how it works out please.

Edited April 7, 2017 by deilenberger

[scanner-1]

Just a thought Bazza...

Did your regular oil change include a cabin air filter change?

I recently bought a 2011 Turbo and thought the HVAC was "overshooting" it's targeted temperature with somewhat erratic fan action. Setting the air flow setting to "soft" had no effect.

A couple days ago I changed out my cabin air filter and discovered there was a sensor that was NOT properly positioned inside the passenger side supply duct--this sensor looks to be easily dislodged during a cabin air filter exchange. 

The jury is still out, but I think this could be a likely solution.

Good luck!

-Scanner

[NOWATERTILL97]

It is the the blower motor regulator, and it is incorporated into the blower motor housing. Porsche has sold hundreds of them recently. Just replaced one in  a 2011, everything works fine now.

[deilenberger]

1 hour ago, NOWATERTILL97 said:

It is the the blower motor regulator, and it is incorporated into the blower motor housing. Porsche has sold hundreds of them recently. Just replaced one in  a 2011, everything works fine now.

 

Interesting. Can the motor regulator be replaced individually?  I have a persistent error on the HVAC module, related to excess current draw by the HVAC fan. I can clear it and it reoccurs. The fan works fine - once it's started.  It does start oddly. It starts at high RPM (and high RPM indicated on the LCD display) - then I hear flappers moving around, and the air velocity drops drastically for a second. Fan speed according to the display has not changed. After the second - the air-velocity increases again. It then may (or may not) repeat this cycle once again. From then on it runs normally.

 

I tried to drop the blower motor to see if I could determine what was going on - but it foiled me on removal. The big-*** (tech-term) bundle of wires that pass beneath it made it almost impossible to get all the screws out that hold it in, and when they were removed I could only drop it about 1/2". Since it was getting late, and I was getting sore from standing on my head in the vehicle - I put it back together.

 

Any hints on either?  Regulator available as a part?  Getting the **** thing out?

 

TIA.

Edited October 5, 2017 by deilenberger

[scanner-1]

Nice to hear you were able to get that fixed!

Since this might be in my future, I am curious as well--were you able to do this yourself? Especially concerned that Don got foiled--haha! What did that part cost?

Related to your problem Don (although probably a long shot considering you just had that area opened up), I also had odd fluctuations with my AC. I didn't pull any codes, but discovered the problem when my passenger's Louboutin's got soaked on a high G turn! Cleared the clogged AC evaporator drain and everything returned to normal.

[deilenberger]

3 hours ago, scanner-1 said:

Related to your problem Don (although probably a long shot considering you just had that area opened up), I also had odd fluctuations with my AC. I didn't pull any codes, but discovered the problem when my passenger's Louboutin's got soaked on a high G turn! Cleared the clogged AC evaporator drain and everything returned to normal.

 

I had the clogged drain - and it was cleared and still is. I've added cleaning it out to the schedule for replacing the cabin filter.

 

That may have been about when this behavior started.. my iCarScan shows the outside/recirc flap is a bit slow to perform.. it does reach the desired position - but it fails the test for doing so (which apparently is position and time based.)  My thinking was that perhaps this flap or the motor got wet and are binding up a bit, so I figured the biggest hole into the HVAC housing is the motor opening..  plus it would give me a chance to lubricate the motor bearings.  If the flap was binding up (and the sound from the HVAC system sounds as if it's switching from inside to outside air) a bit - the control module may make it repeat the function until it gets it right, which could account for the repeated airflow decreases on startup.