Yesterday we noticed extremely low air flow from the AC vents with very little variation between the lowest and highest speed selection. If I turned it down to one bar, waited for the speed to stabilize and turned it all the way up it would blow at a higher speed for a second or two and then reduce speed. Today it wouldn't run at all.

When we got home I got out my code reader and it had two AC faults - Fan over current and fan controller short circuit. I cleared the codes and the fan ran on the very low speed like yesterday. I turned it off after a few seconds so as not to add problems.

Could this be caused by a stopped up filter? I don't think it has been changed in a long time. Is there only one, the one under the glove compartment?

I guess I'll order one and see what happens, but hopefully someone can shed some light on this.

Thanks,

 

most likely the blower motor.
Check out the DIY section. It is not a very involved job:

The only sign of trouble was that regardless of manual or auto on the HVAC, when the fan was signaled for a setting at the 5th or higher bar (the LCD bars that provide the visual reference next to the blower toggle), it would not produce a volume greater than the 4th bar.

Rats, it is the resistor pack. It appears that sometime ago, resistor packs, the IC board to control the fan and the blower were integrated into a single unit. Rats again, this could get expensive.

Did some quick research and found that Porsche was on its 3rd or 4th part number revision 2011-2018 958-572-342-03 at $528.89. It turns out to equal VW Tourag's 7P0820021H at $340. Still rooting around I found Rock Auto had VDO PM 4090 at $134.70 + S&H. Could I be so lucky. Ordered the VDO.

I will let the pics speak for themselves. Same supplier, same county of origin, sames primary casting numbers on the housing.

The R&R is so straight forward. AllDataDIy has some very good pics

1. Torx 20 for the one screw holding the bottom cover on, the rest is a pull down in front (clips) and then pull forward friction fit
2. Disconnect electrical harnesses (12v adapter and the floor light)
3. Ease the plenum out of the way (pay attention to the temp senor)
4. Unscrew quantity 5, 4mm (5/32) screws holding a housing in place. Remove the housing. It it does not move easily, you have missed a screw!
5. Unscrew quantity 2, 4mm (5/32) screws holding the blower in place. It it does not move easily, you have missed a screw!
6. As you ease the blower down, release the harness.

Install new in reverse.

Lastly, PIWIS is not involved!!!

 

THANKS! Love this forum.

 

I'm easily confused. I went to the Rock Auto site and they show five different options for the blower for a 2015 Cayenne Diesel. Some mention they include the controller board, some don't. The VDO doesn't mention the controller, says it comes with the motor and the "wheel". So is there a separate controller? Do some of these motors (all of which say they are for the same car) have a controller and some don't?

Thanks

 

The correct part has the blower motor, squirrel cage and controller board all built into one unit.

All of the ones listed for the 2015 CD will work. the one I ordered and recommend is the one built by VDO PM4090 https://www.rockauto.com/en/partsearch/?partnum=pm+4090

Extensive DIY, discussion and teardown of failed part is here: https://rennlist.com/forums/cayenne-...placement.html

 

I just installed the latest PM4090 revision in my 12 CTT. Continental acquired VDO and this part is now made in China. I believe you'd need to go OEM VW or Porsche for a European made unit at this point.

The casting is exactly the same as shown in threads here but there were fewer labels on my Continental unit. Replacement unit works great nonetheless. At top fan speed you can hear the motor now. Pretty sure my old unit didn't work at top speed so I have nothing to compare it to. I never run it at top speed so I don't care.

For a little over $100, perfectly happy...

 

Can you you provide some more substance to your position that the part is now made in China? Pics of the part's labels? The part I purchased was built in 2019, VDO label and made in Hungary. Pics in the DIY post.

Continental completed that purchase back in 2007. https://www.dw.com/en/protectionists...many/a-2706269 . I see some reporting on it in 2020, 2019, etc that looks like click bait. From what I can tell it i old news.

Continental AG is based out of Germany. https://www.continental.com/en/

VDO is still a brand but is now obviously owned by Continental.

 

Okay, what I said was a recent acquisition should have been described as a recent rebrand. The 2020 announcement was significant - rebranding their aftermarket parts from VDO to Continental https://www.continental.com/en/press...e-continental/

Now, here is my speculation - as of 2020/2021 Rennlist members were ordering the VDO PM4090 from RockAuto and receiving a rebranded OE unit, made in Hungary

My Continental PM4090, with its 2022 manufacture date, is clearly made in China. The OE labels are not there. But I'll be honest, the plastic/metal castings as well as the fan itself look identical to the VDO unit in older photos.

It is therefore plausible that with the 2020 announcement, and as part of the rebrand, VDO/Continental began off-shoring manufacturing for some aftermarket parts. So whereas previously ordering the aftermarket VDO unit got you an identical made-in-EU OE blower motor, this may no longer be the case. I didn't order mine from RockAuto but I'd be curious to see a PM4090 ordered more recently.

The last thing I'll say is I'm not the biggest critic when it comes to made-in-China auto parts. I rebuilt the whole front end of my Audi with unbranded Chinese made control arms (purchased thru Europa parts in NJ) and they've been great for 3 years with no signs of abnormal wear. As is the case with my Continental blower motor, if it works, it works...

 

Good info. Thanks for the details.

 

Thanks guys. I'll look closer and see what I can find. I'm not sure I'm willing to pay 2x or 3x to get a part not made in China, even if such a part exists. Glad to know of your good experience with the China version. And it does say "Assembled in China". May be that is final assembly of parts made elsewhere.

 

Ordered the VDO part from Rock Auto. Also ordered the Bosch filter.

Thanks to everyone for the help, and the DIY post. I think I replaced the filter years ago so I've done most of the work before.