Effect of disconnection or total discharge of battery on electrical systems in the vehicle and the precautions to be taken
Values and faults stored in the control units can be deleted if the battery is disconnected or completely discharged.
- If possible, all fault memories should be checked and, if necessary, printed out before the battery is disconnected.
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.
In some countries (presently the U. S. A. and Canada), after disconnecting the battery, it is necessary to reach the Ready status by a test drive and/or by using the Porsche System Tester DME control module menu). If in doubt about this, contact the relevant importer.
2470 DME control module
With all DME systems, the engine must run for several minutes before the engine control module can relearn the idle speed and mixture adaptation values!
After disconnection of the power supply, the idle speed might change or fluctuate briefly until the throttle valve adjusting unit has been readapted.
The mixture adaptation is also lost.
After the battery is connected:
With the DME, it is necessary to carry out a learning and adaptation routine as described below:
- Switch ignition on for 30 seconds without starting the engine.
- Do not actuate accelerator pedal.
This completes the adaptation of the throttle valve adjusting unit.
When the battery is disconnected and connected, the tire 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.
The steering angle sensor must be re-initialized 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.
The limit positions of the large roof are deleted from the control unit when the battery is disconnected and connected.
- Switch on ignition.
- Press rocker switch upward.
The roof opens and closes completely.
The limit positions of the large roof are now stored in the control unit again.
The limit positions of the power windows are deleted from the control unit when the battery is disconnected and connected.
Perform the following procedure for all power windows:
- Pull rocker switch and fully close window once.
- Pull rocker switch once more.
- Press rocker switch and fully open window once.
- Press rocker switch once more.
The upper end position of the window is stored.
The lower end position of the window is stored.
Clock
The time is deleted when the power supply is disconnected.
The clock is set in the multi-function display.
- Press clock button on instrument cluster.
- Set the time in "Hours" with rocker switch on the wiper switch.
- Press reset switch on the wiper switch.
- Set the time in "Minutes" with rocker switch on the wiper switch.
- Press reset switch on the wiper switch.