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Porsche PCM Issues

Porsche Communication Management Issues
By Tony Callas and Tom Prine

The Porsche Communications Management (PCM) system encompasses all areas of your Porsche’s electronics operations that do not relate to the mechanical operation of the car. PCM would include the electronics for the audio, video, navigation and displays used in your car. For the purposes of this discussion we will focus on the 987-1 and the 997-1 which covers models years 2005 through 2008.

Some owners have experienced problems with PCM equipment and they are surprised when we query about any possible changes to the car made prior to the onset of problems. Is your vehicle completely stock meaning there is no aftermarket electrical equipment, such as an IPOD interface, Satellite radio, Bluetooth component, etc… Almost any aftermarket component can cause issues with the MOST (Media Oriented Systems Transport) Fiber Optic Network architecture.

The components or equipment connected to a Fiber Optic network are organized in a “Set List” that is structured in a specific order. If an aftermarket equipment component is installed it must be properly integrated into this Set List. Any deviation from this exact Set List order may cause any number of problems. Therefore, if the set list is not correct, there may not be any audio, the CD changer may not work or the Navigation System may not function properly or more. The only way to correct a corrupted Set List is with the Porsche factory PIWIS tester in the hands of an experienced technician.

If you have no aftermarket parts installed and the Set List order is confirmed as correct, then performing a vehicle handover with the PIWIS tester thus rebooting the system (the car) is in order. This will return everything back to Porsche’s original settings such as when it left the factory.

There is one test you can perform yourself. This test is specific to the 997-1 which utilizes the type 2 PCM architecture. Note, the 996 utilizes type 1 architecture, the 997-1 utilizes type 2 and the 997-2 utilizes the type 3 architecture. The following description will only work with the type 2 architecture.

There are a number of buttons on the bottom of the PCM fascia just below the screen. Push the far left (Main) and the one second to far right (Trip) buttons simultaneously and hold them down for approximately one second. This will populate a list on the PCM screen which is known as the “Set List”. If the Set List is correct, you will have check marks next to each component denoting that the sequence and all components are nominal. If there are any exclamation marks then this indicates there is a possible problem with that certain component and or the set list is incorrect. To exit the Set List screen, just touch any single button.

Also consider that it is possible for low battery voltage and or a battery disconnection to cause the Set List order to become corrupted. This condition can also be remedied with a factory PIWIS tester to reorganize the Set List.