Test point 13: Elimination:

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2005 Porsche 911, 2004 Porsche 911, 2003 Porsche 911, 2002 Porsche 911, and 2001 Porsche 911. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect plug from control module, check for continuity with ohmmeter on Pin 2 and Pin 3.
If a short circuit is found, check the sensor wires first.
If no fault is detected in the wire, replace sensor. Once the cause of the fault has been found and eliminated, actuate the fore-and-aft adjustment switch. The text in the fault memory changes from present to not present if the cause of the fault has really been eliminated.
If the fault is still present, replace control module.