SERVICE PRECAUTIONS
The following precautionary measures must be taken before disconnecting or total discharge of battery or serious electrical damage can occur
- To avoid triggering siren, on vehicles equipped with an additional alarm siren, battery must be disconnected with ignition switch turned to ON position.
- All loads must be switched off and ignition key removed from ignition switch.
- Never disconnect battery with engine running.
- Ensure battery is securely connected before starting.
- Do not use a boost charger to start engine.
- Never start engine, unless battery is securely connected.
- Battery terminals should be connected without force, to prevent damage to battery housing.
- When jump starting, use jumper cables with overvoltage protection.
- Always disconnect battery before performing any welding.
- After installation, ensure battery is seated correctly. Other dangers exist with a loose battery such as: reduced service life due to vibration, damage to grid plates of battery, damage to battery housing from mounting elements (possible acid leak), or inadequate crash safety.
BATTERY DISCONNECT PRECAUTIONS
After disconnecting battery or replacing ECM, drive vehicle to enable ECM to relearn driveability. Inform your customer that they may experience driveability different from what they are accustomed to until ECM completes relearn function.
Ready Status
After battery is disconnected and reconnected, the "Ready Status" must be obtained following a test drive or using a Porsche System Tester (or equivalent aftermarket scan tool).
Idle Relearn
After disconnecting the power supply, the idle speed might change or fluctuate briefly until the throttle adjusting unit readapts. The mixture adaption is also lost.
To readapt the DME control unit (PCM), perform the following procedure
- Turn ignition on, with engine off for 30 seconds. Do NOT touch accelerator pedal. This completes the adaption of the throttle adjusting unit.
- The engine must run for several minutes before the PCM can relearn the idle speed and mixture adaption values.
Tire Pressure Monitoring
Tire pressure monitoring values will be lost after the battery is disconnected. After reconnecting the battery, drive the vehicle for a short distance. The actual tire pressures will start to display again.
Steering Angle Sensor
The steering angle sensor must be re-initialized after battery is disconnected and connected.
- Turn steering wheel to straight ahead position.
- Turn ignition off then on again twice (do not start the engine yet).
- Start engine.
- From the straight-ahead position, turn steering wheel about 20 degrees to the left and 20 degrees to the right (past the straight-ahead position).
- Drive the vehicle straight ahead for at least one second at a speed above 2.5 MPH.
- The stored fault code in the Porsche Stability Management (PSM) control unit should now be cleared automatically. The PSM indicator light in the instrument cluster should now go out.
Sliding Roof Electric Motor
The sliding roof limit positions are lost when battery is disconnected and connected. To restore settings, turn ignition on (engine off) and press the rocker switch upwards. The roof opens and closes completely. The limit positions are now stored in the control unit.
Power Windows
The limit positions of the power windows are deleted from the control unit when the battery is disconnected and connected.
To restore the settings, manually close each power window as far as it will go. Open it completely, and then press the rocker switch for closing the window again. The power window limit positions are now stored in the control unit.
Supply Voltage Fault Entry
A "supply voltage" entry may be stored in various electronic control units if the battery is completely discharged. This will have to erased from fault memory using a scan tool.