911 Carrera 4 Cabriolet (996) F6-3.6L (2003)
Body Control Module: Service and Repair
Effect of disconnection or total discharge of the battery on electrical systems in the vehicle, subsequent measures:
1. Never disconnect battery with engine running.
2. Never start engine without securely connected battery.
3. Do not use a boost charger to start the engine.
4. Whenever possible, use jump leads with over voltage protection.
5. Always disconnect the battery terminals before carrying out welding work on the vehicle.
6. Wiring harness plugs of control modules or other electronic components must be connected or disconnected with the ignition off.
Exception: vehicles with the additional equipment M 536 (alarm siren with tilt sensor).
Note concerning M 536:
In order to avoid triggering the alarm siren (installed on right next to the battery) of vehicles with M 536, the battery must be disconnected with the
ignition on (all loads must be switched off beforehand).
Control module memories:
Values and faults stored in the control modules 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.
Supply voltage fault entry:
The entry "supply voltage" could be stored in various control modules if the battery has been completely discharged.
Delete the "supply voltage" entry from the control modules in question.
Test drive after connecting the battery:
The fault memories of all vehicle control modules should be read out again after the test drive.
DME control module:
After disconnection of the power supply, the idle speed might change or fluctuate briefly until the idle speed positioner (M 5.2) or the throttle
adjusting unit (ME 7.2) is readapted. The mixture adaptation is also lost.
After the battery is connected:
With the DME ME 7.2, it is necessary to carry out a learning and adaptation routine as described below:
Switch the ignition on for I minute without starting the engine. Do not actuate accelerator pedal.
Switch off ignition for at least 10 seconds.
This completes the adaptation of the throttle adjusting unit.
With all DME systems, the engine must run for several minutes before the engine control module can relearn the idle speed and mixture adaptation
The stored pressure adaptation values are lost if the power supply to terminal 30 is interrupted. This can result in poor shifting quality (rough shift
operations) during the adaptation phase.
Perform a test drive. During the test drive, drive the vehicle with varying load conditions and speeds so that all shift functions (manual and automatic
programs) are executed at least once. This readapts the shifting pressures of the system and thereby re-establishes smooth shifting.
The limit positions of the power windows are deleted from the control module when the battery is disconnected and connected.
Manually close each power window as far as it will go, then press the rocker switch for closing the window again. The limit position of the respective
power window is now stored in the control module again.
The trip counter is set to 0 when the power supply is disconnected.