How to Jump Start a BMW the Right Way

BMWs have the battery in the trunk, but you should NOT connect jumper cables to the trunk battery terminals. Here's the correct procedure.

Why Not the Trunk Battery?

Connecting jumper cables directly to the battery in the trunk can:

• Cause sparks near the battery (hydrogen gas = explosion risk)
• Send voltage spikes through the electrical system
• Damage sensitive electronics

The Correct Procedure

Step 1: Find the Jump Start Terminals

Every BMW has dedicated jump start terminals under the hood:

• Positive (+) terminal: Red cap, usually near the strut tower or fuse box
• Negative (-) ground: A bolt or stud on the engine or chassis

Step 2: Connect Cables (Order Matters!)

1. Red cable to YOUR BMW's positive (+) terminal under the hood
2. Red cable to the donor car's positive (+) battery terminal
3. Black cable to the donor car's negative (-) battery terminal
4. Black cable to YOUR BMW's ground point (engine bolt or chassis ground — NOT the battery)

Step 3: Start the Donor Car

Let it run for 2-3 minutes to charge your BMW's battery slightly.

Step 4: Start Your BMW

Turn the key / press start. It may take a few seconds of cranking.

Step 5: Disconnect (Reverse Order)

1. Black cable from your BMW
2. Black cable from donor car
3. Red cable from donor car
4. Red cable from your BMW

Step 6: Drive for 30+ Minutes

The alternator needs time to recharge the battery. Don't just start it and park it.

After Jump Starting

• Register the battery if it's been deeply discharged — the IBS may need recalibration
• Check for fault codes — deep discharge can trigger various module faults
• Test the battery — if it died once, it may be failing. Get it load-tested.
• Check for parasitic drain — if the battery died without reason, something is draining it

Can I Use a Portable Jump Starter?

Yes — and it's actually the preferred method. A lithium jump pack:

• Connects to the same under-hood terminals
• No donor car needed
• Safer (controlled current)
• Compact enough to keep in the trunk

Recommended: NOCO Boost Plus GB40 or similar — €80-120, fits in the glove box.

BMW-Specific Jump Start Terminal Locations

Model	Positive Terminal	Ground Point
E46	Under hood, right side	Engine lifting eye
E90	Under hood, right side near fuse box	Engine bolt
F30	Under hood, right side	Engine bolt
E60	Under hood, right side	Engine bolt
X5 (E70/F15)	Under hood, right side	Engine bolt
G20	Under hood, right side	Chassis ground stud