How to Jump Start a Volvo S40

1. Switch off the ignition.
2. Connect the auxiliary battery's positive (+) terminal to the positive (+) terminal on your vehicle's battery, marked with a "+" sign.
3. Connect the auxiliary battery's negative (–) terminal to the ground point in the engine compartment near the driver's side spring strut.
4. Start the engine in the assisting vehicle, then start the engine in the vehicle with the dead battery.
5. Once the engine runs, first remove the negative (–) jumper cable.
6. Then remove the positive (+) jumper cable.

• If the auxiliary battery is in another vehicle, make sure the vehicles are not touching.
• Do not touch the jumper cables during the start attempt, as this could cause sparks.

Source: 2011 Volvo S40 owner's manual, PDF page 162. Steps are summarized in our own words (AI-assisted, checked against the cited pages 2026-10-18). Other model years can differ; your manual has the final word.