This will make droptop's day. So, I've gone months without nary a thing.. and the idiot lights have not shown themselves.... but, today at lunch... without iPod even in the mObridge and the PCM OFF... voila' - "PHC Unavailable" and then the dreaded ! (with apologies to Larry for using the dreaded symbol) to engine shutdown... it didn't re-appear after lunch meeting.

Okay, as we know, I'm in a Tit.S not a GTS or V6 manual. The dealer will of course, say, mObridge in the MOST non-approved Porsche modification. So, let's start another long thread about "what it be" and "what it not be".. does PHC really mean "Pig Heretofore Cayenne"?

 

Okay, let me try it another way, any other mObridge users getting a "PHC Unavailable" light (of course, this is after the CDC not found message displays)?!

 

I don't have mObridge but I've had than warning pop up a few times. Dealer couldn't find fault code or replicate. It seems to be some kind of glitch because everything operates fine. Plus, since I'm out of warranty, I'd rather not know because it sounds like it could be expensive to fix.

 

THANKS..that's what I was told long ago.. it is a manual transmission fault/error... makes no sense.. it was one of droptop's "last straws".

 

I thought it had to do with hill descent? Either way, dealer says nothing is wrong, car drives fine, and it just goes away when I restart the car.

 

PHC is Porsche Hill Control.

From what we've seen, the fault is typically caused by the sensor that measures brake pedal travel - it's in the brake booster. Looking at it with the tester, when it fails completely, it shows no signal regardless of pedal position. Signal can be found in the PSM module actual values.

Can't offer any experience with mObridge and its effects on the system.

 

No comment on the problem at hand but I do like this signature:

"'83 US 928S 5sp mostly in discreet, compact containers"

 

Yes, you're correct.. but it a feature only needed "used" in manual transmissions.. i.e. don't stall the car on the "hill" or for parking.. so why getting it in an automatic? droptop oh, where for art thou?

 

Wow, this must be a very new problem..I mean, it couldn't have been something discussed back in the beta (04) days....
MadFox....please check your clutch pedal immediately

 

Yeah, seems odd to me too, but we've seen the same fault (and fix) on manuals and automatics. Also, there is a difference between PHC and PHH (Porsche Hill Holder), which is the manual transmission addition.

 

Is the clutch that gray pad on the left side of the footwell? Made of plastic near the hood release? It doesn't seem to be working.. as it doesn't go ... I'm going to get technical here.. "in or out"? I do keep my foot resting on it but I don't specifically remember doing so on a hill per the TSB. Should I get the clutch pedal replaced under warranty?

 

Since you work in the shop, are you telling me to expect a PHH warning fault too?

 

Well there you go.
You have been 'riding the clutch' for the entire time you've owned the Cayenne.

 

So does it mean my clutch is broken or is it just "Unavailable"? Should I keep my foot off the "clutch" all the time and see if the light stops intermittently appearing?

 

...not if you stop riding the clutch (The "clutch unvailable" message only appears when you ride the clutch after connecting a trailer.)