Disconnect and Reconnect the Battery

Disconnecting the 12 V battery on your Cadillac ATS (2013–2019) is a straightforward job you’ll come to for a battery renewal, before a long storage lay-up, when you’re working on electrics or near the airbags and seat-belt pretensioners, or to recover the car after a deep discharge. On the ATS the battery sits in the engine compartment, so it’s easy to reach without lifting any trim. Take the terminals off in the right order, give the modules a moment, and reconnect the same way in reverse — the car relearns cleanly and you’re back to normal.

Where the 12 V Battery Is

The 12 V battery is in the engine compartment, under a cover. Open the bonnet, lift or unclip the cover, and you’ll find two clamped terminals. The negative (−) is the earth/ground lead, usually black; the positive (+) is red and normally sits under a hinged or press-fit cap. Identify both clearly before you start, because keeping them straight is what makes the job safe.

Getting Ready

• Turn the ignition fully off, remove the key, and take the fob away from the car.
• Switch off the lights, climate, and anything drawing power so there’s no load on the system.
• Note your radio presets and clock — they can drop when the battery is disconnected.
• Wait a couple of minutes after switching off so the control modules power down and sleep.
• Have the right spanner ready (typically a 10 mm nut), plus gloves and eye protection.

Find the Battery First

Disconnecting Safely

1. Confirm the ignition is off, the key is out, and all electrical consumers are switched off.
2. Slacken and remove the earth/negative (−) cable first, then move it clear so it can’t touch the post.
3. Only then loosen and lift off the positive (+) cable.
4. If you’re working near the airbags or pretensioners, wait a few minutes after disconnecting before you begin.

Reconnecting

Reverse the order: fit the positive (+) first, then the negative (−) last, and tighten both clamps securely. Afterwards:

• Don’t move the vehicle until the systems have re-established themselves.
• Re-enter the clock and radio presets that dropped.
• If a window loses its one-touch function, hold the switch fully up at the top limit and fully down at the bottom to relearn it.
• The tyre-pressure monitor may need a short drive to re-store readings on its own.

If Something Isn’t Right Afterwards

• Check both clamps are tight and fully seated — a loose earth is the usual cause of odd electrical behaviour.
• Take the car for a short drive so the modules can see everything working and self-clear transient warnings.
• If a window still won’t auto-close, repeat the hold-at-the-limits relearn.
• Fit a like-for-like battery of the correct size and rating.
• If a light stays on, it has stored a code — look it up on autodtcs.com.

Frequently Asked Questions

Where is the battery on a Cadillac ATS?

In the engine compartment, under a cover. Open the bonnet and unclip the cover to reach the two terminals — there’s no trim to lift, so it’s an easy spot to work in.

Which terminal do I disconnect first?

The earth/negative (−) cable first, and reconnect it last. Removing the ground path first stops a spanner shorting against the bodywork while you’re on the positive side.

Will I lose my radio code and presets?

Note your presets and clock before you start. Disconnecting cuts the memory, so you’ll re-enter the time and stations afterwards. Most infotainment settings return once power is restored.

Does a new battery need coding on an ATS?

A like-for-like replacement of the correct size and rating is what the car expects, and a straightforward swap generally needs no coding. Fit the same battery type it left the factory with.

Will disconnecting the battery reset the service light or clear fault codes?

It can clear some temporary stored codes, but it isn’t a real fix — a genuine fault just sets the code again. It’s not the correct way to reset the service reminder either; use the proper menu procedure for that.

Can I jump-start it instead of disconnecting?

Yes — for a flat battery, a jump-start or a proper charge is usually quicker. Disconnecting is only needed for a renewal, storage, or work near the airbags and electrics.

To relearn a window, hold its switch at the upper and lower limits for a moment. If a warning light stays on after reconnecting, look up the code on autodtcs.com.