Using jump starting with another battery

Updated 16/03/2023

If the starter battery is discharged then the car can be started with current from another battery.

Jump starting requires access to another car's 12V battery as well as jump leads.

P6-1817-CMA-XC40-starter cable fixation points — Charging points for jump starting own car. The appearance in the engine compartment may vary depending on car model and equipment level.

When jump starting the car, the following steps are recommended to avoid short circuits or other damage:

Set the car's electrical system in ignition position 0.

Check that the donor battery has a voltage of 12 V.

If the battery is installed in another car – switch off its engine and make sure that the cars do not touch each other.

Connect one of the red jump lead's clamps to the donor battery's positive terminal (1).

Important

Connect the jump lead carefully to avoid a short circuit and contact with other components in the engine compartment.

Open the positive charging point's cover (2).

Attach the red jump lead's other clamp onto the car's positive charging point (2).

Attach one of the black jump lead's clamps to the donor battery's negative terminal (3).

Attach the black jump lead's other clamp onto the car's negative charging point (4).

Check that the jump lead clamps are affixed securely so that there are no sparks during the starting attempt.

Start the engine of the donor car and allow it to run for a few minutes at a rotation speed higher than normal idle approx. 1500 rpm.

Start the engine in the car with the discharged battery.

Important

Do not touch the connections between cable and car during the starting attempt. There is a risk of sparks forming.

Remove the jump leads in reverse order - first the black and then the red.

Make sure that none of the black jump lead's clamps comes into contact with the car's positive charging point, the donor battery's positive terminal, or the clamp connected to the red jump lead.

Warning

The battery can generate oxyhydrogen gas, which is highly explosive. A spark can be formed if a jump lead is connected incorrectly, and this can be enough for the battery to explode.
Do not connect the jump leads to any fuel system component or any moving part. Be careful of hot engine parts.
The battery contains sulphuric acid, which can cause serious burns.
If sulphuric acid comes into contact with eyes, skin or clothing, flush with large quantities of water. If acid splashes into the eyes - seek medical attention immediately.
Never smoke near the battery.

Note

If the starter battery has such a low State Of Charge (SoC) that the car has no normal electrical functions and the engine is then jump-started with an external battery or a battery charger, the Start/stop function may continue to be activated. If the Start/stop function then auto-stops the engine shortly afterwards, there is a great risk that engine auto-start will fail because the battery has not had the time to recharge sufficiently.

If the car has been jump-started, or if there is insufficient time to charge the battery using a battery charger, the Start/stop function will be temporarily deactivated until the battery has been sufficiently recharged by the car. In an outside temperature of approx. +15 °C (approx. 60 °F), the battery needs to be charged for at least 1 hour by the car. In a lower outside temperature, the charging time may increase to 3–4 hours. The recommendation is to charge the battery if possible using an external battery charger.