Originally Posted by StevieD'Santi

Please forgive me for not introducing myself properly. I'm just so excited to have finished modifying my 991 Multifunction steering wheel buttons to shift up with the right/rear button and down with the left/rear (front buttons deactivated).

I've graduated to my current 991 C2S from a heavily modified Cayman CS (think faster than your ordinary Cayman R) as it has become too hard for me to drive on the roads. But, more on me and my Cayman another time. Here's what I've done by following the advise from others on this and various 991 forums...

Disclosure; Reading Planet-9's Robertsmania Rewire Steering Wheel PDK Buttons instructions got me believing that it possible to do the same on my 991 wheel. However, his car was an earlier Cayman and.. didn't have multifunctions.

As I followed his instruction, I learned several tips that made it easier for you to do it if you have some automotive modification experience. For example:

I covered my nice leather wheel with paper towels and masking tape to prevent any damage that it may be subject to while off the car.

On Robertsmania's instructions:
Step 2. Removing the airbag, I discovered that it was easier to release by with a 3mm standard hex wrench, tilting the the top of the wrench toward the front of the car. That will guide the inserted end towards the metal air bag removal latch that needs to be pushed up.

Step 4. I placed a small slotted screwdriver under the orange tab from the top of the connector to easily raise the tab for connector removal as I couldn't raise it with my fingernail.

Step 12. I strongly recommend getting a set of Harbor Freight's nylon Trim and Molding Tool Set at 6.99 is a bargain if you want not to mar your beautiful MF wheel.

Step 16. Before starting this most difficult step, try unlatching the two plastic tabs inside airbag chamber (pictured in Robertsmania step 31). I think I may have overlooked them when I first tried to open the fascia. Also, if your not doing this on a warm 85 deg day in the sun, a HAIR DRIER WILL MAKE IT A LOT EASIER to release the plastic holding rivets. I particularly found 6Speedonline's Kaz Multi-function wheel upgrade for 997.2 step 14 was most helpful at working the side spoke fascia apart. Using the trim removal tools instead, inserting several tools and an electrician's screwdriver in between gives you the wedging effect that Kaz wrote about. Do not try prying apart with two hands, it may damage the fascia.

Step 19. Skip this section completely as you don't need to remove the circuit boards like I did to design this modification for the 991 multifunction wheel.

Once apart, I discovered a major difference in the connector wiring that didn't apply to my steering wheel. It took me an evening exploring, tracing and scheming the PDK button signals on the 991 Multifunction steering wheel on paper.



Then I came across fontana302 brilliant post describing how Robertsmania's modification can be done without cutting or soldering! So I thought about how can this be done with the PDK/Multifunction? And, this is what I came up with:



Here is the way I reprogrammed the buttons without cutting or soldering a la fontana302:
1. As per my diagram above, remove the #3 wire from connector R2 by first removing the connector from the board (squeezing the release tab first). Then, place a straight pin, the kind you get with a new shirt, in the little hole and under the rectangular latch that holds the wire terminal in the connector. This is best done by first pushing the terminal further into the connector before relieving the latch and pulling the wire out. This effectively prevents the down-shift signal from the right/rear button.

2. Remove the #2 wire from same connector R2 (sends up-shift signal from the right up-shift button) and insert it into the vacant #3 spot that you just removed in the previous step. This disables the right/front button while sending up-shift from the right/rear down-shift button to the PDK controller.

3. Remove the #6 wire from the connector R1 and connect it to the end of the wire you removed from R2 #3 in step 1. Use a piece of shrink tubing to keep them connected by shrinking it with with a solder iron. This way the modification may be undone (I also folded a small copy of the modification diagram and stuck it under the harness for future reference). This step re-routs the down-shift signal from the left/rear button directly to the PDK controller.

4. Remove the #8 wire from connector R1 and insulate the terminal with a shrink tube. This disables the left/front button from sending up-shifts.

During the installation of the airbag, there was another catch that I missed that Robertsmania found, causing the horn to always beep when turning on the ignition... There are two small plastic latches illustrated in his step 31 that must be depressing with a screw driver before the fascia can become properly seated.

So if you want your PDK/Multifunction to drive like race car give this a try. Or, give it to a tech who can do it for you. It was a fun mod and makes me think twice on spending $1000. to add paddles. Plus, I think its more functional and aesthetically pleasing to boot.

Thanks,
-Stevie


Original PDK/Multifunction Shift Functions