Emergency Starting with Jumper Cables

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If the battery is discharged, e.g. in winter or after the car has been parked for a long time, the battery of another car can be used for starting with the help of jumper cables. Make sure the voltage of both batteries is the same. Both batteries must be 12 volt types. The capacity (Ampere hours, Ah) of the booster battery must not be substantially less than that of the discharged battery.

The discharged battery must be correctly connected to the vehicle's electrical system.

f Please observe the chapter "BATTERY" on Page 236.

f Please observe the chapter "EMERGENCY UNLOCKING OF THE LUGGAGE COMPARTMENT LID" on Page 235.

Note f Do not try to start the car by pushing or towing. Damage to the catalytic converters and other components of the car may result.


Risk of damage and serious personal injury due to short circuit.

f Use only jumper cables of adequate diameter cross-section and fitted with completely insulated alligator clips.

f Follow all warnings and instructions of the jumper cable manufacturer.

f When connecting jumper cables, make sure that they cannot get caught in any moving parts in the engine compartment. The jumper cables must be long enough so that neither vehicles nor cables touch another.

f The vehicles must not be in contact, otherwise current might flow as soon as the positive terminals are connected.

f The cable clamps must not be allowed to contact each other when one end of the jumper cables are connected to a battery.

f Ensure that tools or conductive jewelery (rings, chains, watch straps) do not come into contact with the positive jumper cable or the positive battery post.

f Improper hook-up of jumper cables can ruin the alternator.

Danger of caustic burns.

f Do not lean over the battery.

Danger of gas explosion.

f Improper use of booster battery to start a vehicle may cause an explosion, resulting in severe personal injuries.

f Keep sources of ignition away from the battery, e.g. open flame, burning cigarettes or sparking due to cable contact or welding work.

f A discharged battery can freeze even at 23°F/-5°C.

Before connecting jumper cables, a frozen battery must be thawed out.

Connect jumper cables in the following sequence:

Always observe the sequence below:

1. Connect the positive lead (red) to the positive terminal of the discharged battery first, then connect it to the positive terminal of the donor battery.

2. First connect the negative cable (black) to the negative terminal of the donor battery, then connect it to a suitable grounding point on the vehicle with the discharged battery. This grounding point must lie as far as possible from the battery.

For example, a solid metal part or the engine block are suitable grounding points.

If no suitable grounding points are to be found on either vehicle, the negative cable must carefully be connected directly to the negative terminal of the battery.

If a suitable grounding point is to be found only on the donor vehicle, the negative cable must first be connected to the terminal of the discharged battery, then to the grounding point of the donor vehicle.

3. Run the engine of the donor car at a higher speed.

4. Start the engine.

An attempted start using jumper cables should not last more than 15 seconds. Then allow a waiting period of at least one minute.


Before disconnecting the jumper cables, electrical loads such as the heated rear window and the heating fan blower should be switched on (the vehicle's lights must not be switched on). This reduces voltage peaks which may occur when disconnecting the jumper cables.

With the engine running, remove both jumper cables in reverse order.

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DIY Battery Repair

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  • SHAY
    Where are jumper cables hooked up on 2000 porche 911?
    10 months ago

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