What To Do After Replacing Your Car’s Battery

So you just replaced your car battery. Start by driving the car for about 20 to 30 minutes, then reprogram your radio presets.
Written by R.E. Fulton
Edited by Melanie Reiff
Reviewed by John Davis
replacing your car’s battery
, drive the car for about 20 to 30 minutes to reset the computer and charge the new battery before reprogramming your radio and anti-theft systems. 
  • Most cars need a new battery every three to five years.
  • When you replace the battery, certain systems such as the electronic control unit are reset and need to be serviced.
  • Proper maintenance can prolong the life of your car battery.

1. Run the car for 20 to 30 minutes to charge the new battery

Why you need to run the car: Your car’s
charges the battery while the car is on, so running the vehicle gives the alternator a chance to do its magic, juicing up your new battery. 
How to do it: Turn the car on and around for about 20 minutes. In addition to charging the battery, this gives your car’s electronic control module (ECU) a chance to detect any errors. 
If it doesn’t work: If you’re not able to start the car after replacing the battery—or if the car dies again shortly afterward—it’s likely that you’re actually dealing with a faulty alternator, not a dead battery. Bring your car to a mechanic for repairs or an alternator replacement (typically $550 to $500). 

2. Reset the vehicle’s computer

Why you need to reset the computer: Your car’s computer—the ECU—reads data from your vehicle while it’s in operation, and a battery replacement disrupts this process. It needs a chance to clear error codes after a new battery is connected. 
How to do it: Your ECU should reset on its own while you drive the car after reconnecting the new battery. If it doesn’t, there are two more ways to perform a reset:
  • If you have a small wrench, use it to detach the positive battery terminal for about five to fifteen minutes and reattach it. 
  • If you have an OBD-II scanner, use it to clear any error codes. 
If it doesn’t work: If you’re not able to reset the ECU on your own, there could be a problem with the ECU itself. If you still see warning lights,
a professional inspection
should cost between $106 and $129. 

3. Reprogram your radio presets and reset the anti-theft system

Why you need to reprogram these systems: The data that your ECU stores includes information about your favorite radio stations! These will typically be reset after you replace the battery, along with your anti-theft system. 
How to do it: To set your radio presets, tune to the station you want and hold down the preset button until the screen displays your chosen number. To reset your car’s anti-theft system, consult your owner’s manual. 
If it doesn’t work: If you’re unable to reprogram these systems, there may be an electrical fault or a problem with the computer. Check with a trusted mechanic. 

4. Clean the battery terminals regularly

Why you need to clean your battery terminals: Most car batteries last between three and five years, on average. You can extend your battery’s longevity with regular maintenance. 
How to do it: Turn off your car, disconnect the battery, and inspect the terminals and cables visually. If you notice corrosion on the terminals: 
  • Use an old toothbrush and a baking soda solution to scrub it away. 
  • Wipe the terminals down and allow them to dry completely. 
  • Apply a small amount of petroleum jelly to the terminals to lubricate and protect them. 
If it doesn’t work: If you notice any problems with your battery, including an
illuminated battery light
on your dashboard, bring the vehicle to a trusted mechanic for diagnosis and maintenance. 
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