It looks like you cannot disable just the PSM. With some informed assistance, I disconnected the steering angle sensor. The hope was that this would fault just the PSM portion of the vehicle control but unfortunately, it drops both the ABS and PSM.

So, it looks like I have fewer, less attractive options:

1. I will try to talk to Porsche Motorsport to see if I can “upgrade” the system to a racing ABS only system.
2. Try to swap a GT-2 ABS system. This could only entail an ECU switch and maybe some harness work.
3. Pull the complete system and put in a dual master cylinder system and modulate, like Rick Gilhart did.

I know 3 works, but I would like 1 or 2.

Shame on Porsche for doing this! At least they recognized some of the failure and have “improved” the system.

Another enhancement to PSM for 2005 gives the enthusiast driver more control over the system. PSM can be turned off through a switch on the dashboard. In the past, PSM automatically reactivated when the brake pedal was depressed, but for 2005 the system reactivates only when the pedal is pushed hard enough to exceed the ABS control threshold on at least one front wheel. This change allows the enthusiast driver more dynamic freedom, including slight use of the brakes in curves.