These instructions apply to the Lexus GS Mk2 (S160) 1997-2005.
For other models, please choose your vehicle here.
Disconnecting the 12 V battery on your Lexus GS (1997–2005) — the S160 GS 300 / GS 430 — for a new battery, winter storage, or work near the airbags is a straightforward job. The battery is in the engine bay, and as long as you take the terminals off and put them back in the correct order, the car relearns the handful of settings it loses within a short drive.
Most owners disconnect the GS’s battery for one of a few reasons: a straight renewal when it’s cranking slowly, to stop a slow drain flattening the car over winter storage, before doing electrical or bodywork jobs, or to power the car down cleanly after a jump-start. Both the six-cylinder GS 300 and the V8 GS 430 are petrol cars, so there is only the one 12 V battery and no high-voltage system to be careful of.
Find the Battery First
Identify the terminals before you touch a spanner: the negative post wears a black cover and a − symbol, the positive is red and marked +. Lift off the plastic cover for clear access.
The 12 V battery is in the engine compartment, under a cover (this GS is petrol, not a hybrid). Note your radio presets before you start.
Getting Ready
- Switch the ignition fully off and put the key well away from the car.
- Turn off the headlights, climate, radio and any accessories so nothing is drawing current when the connection breaks.
- Write down your radio presets and note any security-code details in case you’re asked for them on power-up.
- Give the modules a minute or two to power down after switching off.
- Have the right spanner (usually 10 mm), gloves and eye protection ready.
Disconnecting Safely
- Switch everything off and confirm the ignition is dead.
- Disconnect the negative (−) terminal first, lift the clamp off the post and tuck the cable clear so it can’t spring back onto the terminal.
- Then disconnect the positive (+) terminal.
- Working near airbags or seat-belt pretensioners? Wait a couple of minutes after disconnecting before starting such work, so the airbag system fully discharges.
Reconnecting and Re-initialising
Reconnect in reverse: positive (+) first, then negative (−) last, and tighten both clamps firmly — a loose terminal is the most common reason a car feels wrong afterwards. The GS then relearns a few items as you drive:
- Clock and radio presets — reset the time and re-store your stations.
- Steering angle / stability — settles after a short, steady drive with a full lock each way.
- Power windows — if one-touch is lost, pull the switch up and hold at the fully-closed position for a moment to re-teach it.
If Something Isn’t Right Afterwards
- Check the clamps are tight first — most post-disconnect gremlins are simply a loose terminal.
- Warning lights usually clear after a short drive once the systems re-check themselves.
- Redo the window relearn if auto-up hasn’t come back.
- The gear lever won’t leave ‘P’ after a flat battery? Use the console shift-lock release — see our GS shift-lock release guide.
- A persistent light stores a code — look it up on autodtcs.com before spending money.
Frequently Asked Questions
Where is the battery on a Lexus GS 300 / 430 (1997–2005)?
In the engine compartment, under a cover. Both the GS 300 and GS 430 are petrol, so there’s only the one 12 V battery and no high-voltage system to avoid.
Which terminal do I take off first?
Negative (−) off first when disconnecting, and reconnect it last. Positive (+) goes back on first. That order stops a spanner shorting to the body while the battery is live.
What needs resetting afterwards?
The clock and radio presets, the one-touch windows, and the steering-angle learn. Most of it settles on a short drive; the windows may want a quick pull-and-hold to restore auto-up.
Do I need to wait near the airbags?
Yes — give it a couple of minutes after disconnecting before working on the airbags or seat-belt pretensioners, so the system fully discharges first.
Does a new battery need coding on the GS?
No. A like-for-like 12 V battery is a straight swap on this generation with no registration step. Fit it, reconnect in the right order and let the car relearn.
Will the remote key still work after disconnecting?
It usually does. If the remote stops locking the doors after the battery has been off, see our GS remote-programming guide to re-pair it.
Independent guide — not affiliated with Lexus. Always follow your official service manual and safety precautions. Read our full disclaimer.