pontifex4

Thanks, Loren.  I hadn't heard that -- I'll see if I can find a shop with a PIWIS near me.

On 12/31/2020 at 5:47 PM, GSpence2 said:

If I am not mistaken CC control inputs would be stored in the DME. If yours is acting up you may have a DME with an internal short or coding issue. Hopefully you only have a bad switch as opposed to needing a new DME.

Thank you, I hope I don't have a bad DME!  Notably, everything else works fine, I haven't changed anything except the battery, so I don't suspect improper coding.

This is on a 2004 Cayenne S Titanium.

Question:  Where is the speed setting for the cruise control stored, i.e. in which module? 

When you press the end of the stalk to set cruise control, that value is saved until you turn the car off.  That value must live somewhere.  Where?

My issue: 

• When driving, the cruise control will periodically cancel AND forget its setting
• The cruise control icon on the dash turns off when this happens, then immediately back on
• No value is stored in the cruise control afterward (i.e. "resume" doesn't work, I have to set the speed again by pressing the "set" button at the end of the stalk)
• The steering wheel button lights also blink once when this happens (the ones which are toggled with the redundant buttons on the back of the wheel at 9:00 and 3:00)
• Notably, if I turn those same steering wheel lights off BEFORE one of these events, they turn on AFTER the event, regardless of the setting before the event, as though there has been a reset of that module

To me, this points to a module that stores information that doesn't persist through a restart (i.e. key turned off, then car started).  If I can figure out which module that is, I can be more targeted in my search for the cause.

So far, I've tried (unsuccessfully):

• New brake pedal switch
• New battery and cleaning battery contacts as well as grounds near battery (so far only those)
• Re-soldering harness splices in driver's footwell/dead pedal area (two were marginal)
• Fully charging battery with a CTEK 4.3 (battery drain has not been an issue)

Just an update to this from my own experience: changing the round switch did not fix the high beam problem.

les_gs called it right. Switch was defective. Fixed problem. Part was @$125 and a relatively easy install(so said my techy friend). My car is a 2001 C2 Tiptronic. Replacing stalk part is more expensive(double) and much more time to install

Thank you. Much appreciated. I'll order the round switch.

I would be interested to know whether this worked for the original poster: my low beams (Litronic) turn on when I rotate the headlight switch as they should, but my high beams (halogen) only work when I pull the stalk, not when I push it forward. This is on a '99 with Litronics.

Sorry for dragging this up from the depths, but I just wanted to verify that mine is behaving normally, since it only seems to do this when I start it when it's already warm.

When I start it cold, it doesn't seem to do it.

Thanks,

Charlie.