Battery self-discharge

Depending on vehicle equipment, the current draw of the various control units in the standby state adds to the battery's natural self-discharge. Therefore, the battery of a parked vehicle should be recharged at least every 6 weeks. If parasitic current drain is suspected^, check the vehicle electrical system as follows:

• Use a fully charged battery for testing.

• On the ammeter (measuring range 0–5 mA and 0–5 A), select the highest measuring range. Disconnect the earth lead (-) from the battery. Caution: this will erase the "operating values" from the memory of the electronic injection control unit, and the anti-theft key code and stored stations from the radio memory. Therefore, be sure to read the notes in the chapter "Removing and installing the battery" before disconnecting.

• Connect the ammeter between the battery negative terminal (-) and the earth lead (-). Connect the ammeter positive (+) terminal to the earth lead (-) and the ammeter negative terminal to the battery negative terminal (-).

• Switch off all consumers, disconnect the clock (and other permanent consumers) if fitted, and close the doors.

• Switch back from the ampere range to the milliampere range until a readable value is displayed (1-3 mA is permissible).

• Disconnect the various circuits one after another by removing the fuses. If the reading drops to zero when one of the circuits is disconnected, the fault is in that circuit. Possible faults: corroded and dirty contacts, chafed wiring, internal short circuit in units.

• If no fault is found in the fused circuits, disconnect the wiring from the unfused units, such as the alternator and starter motor.

If the reading drops to zero when disconnecting one of the unfused units, overhaul or replace the affected component. In case of current loss in the starter* or ignition system, always also check the ignition/starter switch according to the wiring diagram.

• Connect the battery negative cable (-).

Set the clock.

• Enter the radio anti-theft code.