Jump-Start the Car

If your fourth-generation Subaru Legacy (BL sedan / BP wagon, 2003–2009) will not crank, a flat 12 volt battery is the usual cause. The battery sits in the engine bay, so jump-starting with another vehicle or a jump pack is simple if you connect the leads in the right order.

How to jump-start the car

Use a good set of jump leads or a lithium jump pack. Park the donor car close but do not let the two vehicles touch, and switch both ignitions off before you connect anything.

1. Switch off the ignition and all electrical consumers in both cars.
2. Open the hood and find the battery and its positive (+) and negative (−) terminals in the engine compartment.
3. Connect one end of the red lead to the flat battery’s positive (+) terminal.
4. Connect the other end of the red lead to the donor battery’s positive (+) terminal.
5. Connect one end of the black lead to the donor battery’s negative (−) terminal.
6. Connect the other end of the black lead to a bare metal engine ground point on the Legacy — a bracket or engine lifting eye, away from the battery — not to the flat battery’s negative post.
7. Start the donor car and let it run for a few minutes.
8. Start the Legacy. Once it is running, remove the leads in the reverse order: engine ground first, then the donor negative, then both positive ends.
9. Drive or run the engine for at least 20–30 minutes to recharge the battery.

Grounding the black lead to the engine rather than the battery’s negative post keeps any spark away from the battery, where flammable gas can collect.

After a jump-start

Because battery power was interrupted, reset the clock and, if the auto-up windows have stopped working, initialize the power windows. If the car will not hold a charge or goes flat again, have the battery and charging system tested.

Frequently asked questions

Where do I connect the negative lead?
To a clean, unpainted metal point on the engine of the flat car, not to the battery’s negative terminal. This is the safest ground.

Can I jump-start from inside — is there a remote terminal?
On this generation the battery is accessible in the engine bay, so connect directly to the terminals and an engine ground.

The car started but died again — what now?
The battery may be too weak to hold a charge, or the alternator is not charging. Have both tested rather than repeatedly jump-starting.

If the battery warning or another light stays on after a jump-start, read the stored fault code to see what the car is reporting — you can look it up on autodtcs.com.