Effects Of Disconnection Or Total Discharge Of Battery On Electrical Systems In The Vehicle And Precautions To Be Taken
Information
Control unit memories
Values and faults stored in the control units can be deleted if the battery is disconnected or completely discharged.
- If possible, a VAL (Vehicle Analysis Log) should be created and stored before disconnecting the battery.
Information
Supply voltage fault entry
The entry "supply voltage" may be stored in various control units if the battery has been completely discharged.
- Delete the "supply voltage" entry from the control units in question.
Information
Ready status
In some countries (presently the USA and Canada), after disconnecting the battery, it is necessary to reach the Ready status by performing a test drive and/or by using the Porsche System Tester (DME control unit menu). If in doubt, contact the relevant importer.
Information
Tyre Pressure Monitoring (TPM)
When the battery is disconnected and connected, the tyre pressure is first displayed as "- - - ".
- Once the battery has been disconnected and work is complete, the vehicle must be driven for a short distance.
The actual pressures will then be displayed again.
Information
Steering-angle sensor
The steering-angle sensor must be re-initialised when the battery is disconnected and connected.
- Turn wheels to straight-ahead position.
- Switch ignition off and then on again twice.
- Start engine.
- From the straight-ahead position, turn steering wheel approx. 20° to the right, past the straight-ahead position.
- Drive the vehicle straight ahead for at least one second at a speed above 4 km/h (2.5 mph).
The steering-angle sensor segment is recognized again in this process.
Once the sensor has been successfully initialized, the fault code that is stored in the fault memory is documented using the fault deletion counter.
The fault memory erases itself automatically.
The PSM indicator light in the instrument cluster goes out.