Work Instructions After Disconnecting the Battery

Work Instructions After Disconnecting The Battery

Effect of disconnection or total discharge of the battery on electrical systems in the vehicle, subsequent measures

NOTE:
- 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.

- Never disconnect battery with engine running.
- Never start engine without securely connected battery.
- Do not use a boost charger to start the engine.
- Whenever possible, use jump leads with overvoltage protection.
- Always disconnect both battery terminals before carrying out welding work on the vehicle.
- 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).

Control module memories

Problem Remedy
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

Problem Remedy
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

NOTE: The fault memories of all vehicle control modules should be read out again after the test drive.

2470 DME control module

NOTE: 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.

Problem Remedy
- After disconnection of the power supply, the
idle speed might change or fluctuate briefly
until the throttle adjusting unit (ME 7.8) is
readapted. After the battery is connected.
With the DME ME 7.8, it is necessary to carry out a learning and adaptation routine as described below:
1. Switch the ignition on for 1 minute without starting the engine. Do not actuate accelerator pedal.
2. Switch off ignition for at least 10 seconds.
This completes the adaptation of the throttle adjusting unit.
- The mixture adaptation is also lost.

6452 Power windows
Problem Remedy
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.

90 25 Instrument cluster
The trip counter is set to 0 when the power supply is disconnected.

9030 Clock

NOTE: In the case of vehicles with PCM, the date and time are deleted when the battery is disconnected:

Problem Remedy
The time is deleted when the power supply is
disconnected. - Enter the current time again.

9023 Fuel level display

Problem Remedy
- If the power supply is interrupted by a
discharged or disconnected battery with the
tank containing less than 19 l, the calculated
value for the range on remaining fuel in the
instrument cluster will be incorrect or deleted. - Fill the tank; then the fuel level sensor is in operating range and its display precision is guaranteed.

- If the tank contains less than 19 l, it is
possible that the fuel level warning light is
no longer activated.
- If the power supply is restored with the fuel
level at less than 19 l, it is possible that the
fuel level display may subsequently display
an incorrect value.

This may lead to the vehicle breaking down.

Remedy

9120 Radio

Problem Remedy
The radio reverts to the Code function when the
battery is disconnected and is thus no longer
ready for operation. 1. Input the radio code.
2. If the code card is unavailable, the radio code can also be read from the DME control module (under "Vehicle data").
3. It is also possible to gain this code from the Porsche IPAS.

9110 PCM

Problem Remedy
- The PCM reverts to the Code input function
when the battery is disconnected and is thus
no longer ready for operation. 1. Input the PCM code. If the code card is unavailable, the PCM code can also be read from the DME control module (under "Vehicle data").
- When the power supply is disconnected, the
built-in GPS receiver loses the so-called
almanac containing the satellite orbital paths. 2. It is also possible to gain this code from the Porsche IPAS.
- The date and time are deleted when the
battery is disconnected. 3. Switch on the PCM with a free panoramic view for approx. 20 minutes (to load GPS almanac).
- Radio stations stored by the customer are
no longer displayed. 4. The date and time are also adopted once the GPS almanac has been loaded; it may be necessary to change over to summer time (daylight-saving time).
- If the telephone card was inserted and the
telephone was ready for operation, the
telephone is subsequently disabled. This time is transferred to the instrument cluster. If the time is then manually changed by means of the instrument cluster, this time is adopted by the PCM and synchronised with GPS time.
5. The stored stations are displayed again when station buttons 1 to 6 are pressed.
6. The telephone is enabled again when the telephone PIN code is entered with the SIM telephone card inserted.