These instructions apply to the Chrysler 300 Mk1 (LX) 2004-2011.
For other models, please choose your vehicle here.
Disconnecting the 12 V battery on a Chrysler 300 / 300C (LX, 2004–2011) is a routine job for a battery change or before electrical work. There’s no battery registration on this generation, but you should let the modules settle for a couple of minutes first and have your radio code ready. This guide covers the safe order of work.
Where the Battery Is
On most 300/300C models the battery is in the engine bay. Lift any cover to reach the two terminal clamps. Fit a like-for-like battery if you are renewing it — match the original size and cold-cranking rating, especially on the HEMI V8.
Before You Disconnect
- Note your radio code and personal settings.
- Turn the ignition off and make sure all electrical consumers are switched off.
- After switching off, wait 2 minutes before disconnecting — this lets the modules power down cleanly.
- If working near airbags or seat-belt pretensioners, allow the system to discharge before handling those parts.
Disconnecting — Correct Order
- Turn the ignition off and wait 2 minutes.
- Slacken the negative (−, earth) terminal first and lift the lead clear.
- Only undo the positive (+) terminal if you are removing the battery completely.
Reconnecting — Correct Order
- Connect the positive (+) lead first, then the negative (−) earth lead last. Tighten both firmly.
- Turn the ignition on for a few seconds before starting the engine.
What to Reset Afterwards
- Enter the radio code and reset the clock, presets and personal settings.
- If the power windows lose one-touch, re-teach each one by holding the switch fully up (closed) for a moment.
- The car may relearn its idle and transmission shift adaptives over the first few miles — a slightly different feel at first is normal.
If a Light Won’t Clear
One or two lights right after reconnecting is normal and should clear on a short drive. If the airbag, ABS or engine light stays on, a fault code was logged — reading it needs an OBD scanner, and you can look up what a Chrysler code means on autodtcs.com.
Registering or Coding the New Battery
Depends on the model. Cars with a battery sensor (IBS) should have the battery reset/registered with a diagnostic tool (dealer or a capable scanner) so the charging system treats it as new; models without a sensor need nothing extra.
Frequently Asked Questions
Do I need to register a new battery on a 300C?
No — this generation has no battery coding. Fit the correct battery and restore your settings.
Where is the battery on a Chrysler 300?
In the engine bay on most models. (Note: the closely related Dodge Charger/Magnum sometimes mount it differently — on the 300/300C it’s under the bonnet.)
Will I lose my radio?
The unit may ask for its security code after a power loss. Have it ready, or use a memory-saver to avoid it.
How long should I leave it disconnected?
Around 10–15 minutes with the doors shut lets the modules power down fully.
To clear the oil-change reminder after a service, see our Chrysler 300 oil-change indicator reset guide.
Independent guide — not affiliated with Chrysler. Always follow your official service manual and safety precautions. Read our full disclaimer.