Coding an alternative tire size?

[spooltime]

Has anyone ever successfully used the Durametric to add an alternative tire size to the TPMS control module? Porsche documentation states there is a programmable field available to do this, and in the control module section of the Durametric software, the coding function takes you to a screen also showing the "freely programmable" field. Not being a programmer or having access to any coding documentation, I could not figure out what "code" I needed to input in order to get the TPMS to display 295/35/21 as a tire size option, summer tire, partial load. Anyone have a clue?????

Right now, I simply have TPMS turned off; I'd rather have it active.

Edited May 30, 2014 by spooltime

[wvicary]

I've not tried to change the coding and might be best to contact Durametric for advice.

[JFP in PA]

Isn't the tire size option built into the TPMS on board dash display system?

Check your owner's manual for information concerning how to select this option.

From a 2011 Cayenne owner's manual (http://www.porscheownersmanuals.com/2011-cayenne/4/123/Tires):

"Entering Tire Data and Display

Incomplete entries or selection of the wrong tires on the multi-purpose display affect correct indication of warnings and messages.

• The settings must be updated in the "Tire pressure" menu after changing a wheel, filling with tire sealant or adding air (after previous warning "Tire pressure!").
• Please see the chapter "RED WARNING – TIRE PRESSURE!" on page 125.

The new tire type and tire size must be selected even if the settings for the new set of wheels are the same as for the old wheels.

[spooltime]

Yes, there are certain tire options pre-coded into the TPMS "setting" menu, but it is possible to code in one available field for a tire size not among the pre-coded in selections. There's a reference to this in the shop manual, and if you go into the coding section for the TPMS module, you can even see the available field to code. I'll take a screen shot of the coding section and post it up later. Basically, I'd like to add a 21" wheel/tire option to my '06.

It's probably a piece of cake to do with the PIWIS; maybe not so much with my Durametric.