System Description

General Information On The Fault Memory
The fault memory of the control module can save up to (80) different faults simultaneously. If the fault memory is full, the new fault overwrites the oldest fault. The fault memory content of the Tiptronic control module is maintained even in removed state.

Fault code setting conditions
Fault codes can be set in various circumstances, e.g.:
- battery disconnected
- plug connections disconnected
- faulty coding
- power failure
- etc.

In these circumstances, no fault is present in the system and the fault memory must be erased.

Standard fault codes in accordance with ISO 15031
Diagnostic fault codes, which can be issued by the control module, are standardised in accordance with ISO 15031. This ISO standard is based on SAE J 2012.

The fault code (DTC = Diagnostic Trouble Code) is always a 5-character alphanumeric value, e.g. P0100.

The first character of the code (a letter) identifies the system that set the code. In all, there are 4 system types:
- P for Powertrain (all OBD2 fault codes begin with this)
- C for Chassis
- B for Body
- U for future systems.

The P codes for powertrain are divided into two main categories in accordance with ISO 15031:
- Uniformly standardised codes: P0XXX and P2XXX; these are the same for all manufacturers
- Manufacturer codes: P1XXX and P3XXX; only the first three characters are standardised here (example: P13XX for ignition system diagnosis or misfire detection), the last two digits can be selected freely by the manufacturer.

Only the P codes are required for OBD II.

The standardised codes are subdivided as follows:
P001 to P0299 Fuel and air proportioning
P03xx Ignition system and misfire detection
P04xx Additional exhaust regulations
P05xx Speed and idle speed control
P06xx Computer and output signals
P0700 to P0999 Transmission

P2000 to P2299 Fuel and air proportioning
P23XX Ignition system and misfire detection
P24XX Additional exhaust regulations
P25XX Additional input signals
P26XX Computer and output signals
P27XX Transmission
P28XX Reserved
P29XX Fuel and air proportioning

Troubleshooting procedure
Troubleshooting can only be performed when the fault is present. In other words, specific troubleshooting can only be performed in accordance with instructions (given under Diagnosis/troubleshooting for each fault code) if the entry has the status present in the fault memory.

If the fault is currently not present, please check the following:
- Diagnostic conditions are met
- All plug connections and ground points of the affected current path are OK.
- View the fault frequency counter in the Porsche System Tester II 9588 using the fault memory Info key F8 under Extended fault memory and try to reach conclusions about eliminating any loose contacts in the system.