Can I Disconnect My BMW Battery?

Lift up on the panel covering your battery after opening the trunk. Remove the negative battery terminal’s bolt with a 10mm socket, remove the terminal from the battery post, and place a barrier between the post and the terminal (microfiber towel will work). Reverse directions for a reconnect.


D: None of the preceding options. To a battery tender or maintainer, connect it (“smart charger”). Otherwise, a dead battery can be waiting for you when it’s time to bring the automobile out of storage. Batteries can’t keep a charge forever.

In a late-model BMW, there is an extra danger when disconnecting or removing the battery: care must be taken to prevent the trunk from closing accidentally. It might not be possible to open the trunk without battery power in order to reconnect the battery.


To change and register a BMW battery yourself, adhere to these instructions:

Set your BMW down. Remove the key while turning off the ignition, but leave the car unlocked. Put your intelligent key at least 30 feet away from the vehicle if you have one.

find the battery Most BMWs have the batteries in the trunk, however some older models had it in the engine compartment. Locate the BMW battery on the passenger side of the trunk floor by opening the trunk. The battery is located on the floor of the trunk if you have a BMW station wagon. To reveal the battery, remove the lining.

To disconnect the negative battery terminal, use a 10mm wrench. Stay away from the negative battery terminal when resting the cord.

Remove the battery’s positive terminal. After that, unplug and take out the positive battery cable. To identify the 10 mm nut that needs to be loosened, you must lift the red plastic cover.

Take the battery bracket off. A bracket on the side and a bracket on top hold the battery in place. By first removing the two 13 mm bolts pointed out by the white arrows below, you can remove the top bracket.

  • It’s time to take out the old battery right now. They are substantial batteries. To lift the old battery, seek assistance.

Put in the fresh battery. Make sure the new battery is properly seated by slowly lowering it into place.

dependable battery Replacing the bracket Avoid overtightening them to avoid damaging the battery casing. A lead-acid battery installation requires that the vent pipe be connected. This is required to prevent a buildup of gasses from the vent hole inside the trunk.

Battery posts should be cleaned. To clean the battery clamps, use a battery terminal brush. Glue the battery terminals together.

  • First, connect the battery’s positive terminal.
  • Last to connect is the negative terminal.
  • The batteries must be registered with an OBD-II scan tool as the final step. An OBD-II scanner that can detect a BMW battery is required. To register the battery, adhere to the scanner’s instructions.

Your car’s battery charge history is reset throughout the BMW battery registration process. Any battery data that was saved as well as the preceding battery’s temperature statistics are deleted. The technique won’t erase the odometer reading.

Your new battery could fail before its time if you replace a BMW battery but don’t register the old one. You could occasionally encounter electrical problems or alerts on the instrument cluster.

What happens if I remove the battery from my BMW?

As long as the battery isn’t overcharged, BMW uses a sealed AGM battery that doesn’t release hydrogen gas. That makes it possible for it to be positioned inside the vehicle as opposed to under the hood. There is absolutely no problem keeping it unconnected indefinitely, as others have stated.

Is it acceptable to unplug the automobile battery?

Warning: Never separate the battery from your car while the engine is running or the ignition is turned on, regardless of the year, make, or model. By doing so, the electrical system can experience a high-voltage spike that could harm electronic modules and/or the charging system.

Does removing the battery reset the BMW ECU?

To reset an ECU, you don’t need to unplug your car’s battery from both terminals.

To reset an ECU, you can choose to unplug the battery from both terminals, but it’s not necessary. Simply cutting off the electricity from the car battery to the ECU will reset the ECU in your vehicle. Disconnecting the negative cable from the negative terminal is the most effective approach to interfere with the ECU’s power supply.

Is it harmful to unplug the automobile battery?

There are a variety of reasons why you might need to unplug the battery from your automobile, but will doing so harm the computer in your vehicle? We looked into all the best sources to learn how to carry out this procedure and what sorts of bad effects it could have on your car’s computer in order to assist you find the answer to that question. This will enable you to assess if it will be worthwhile or whether taking a different path is preferable in your circumstances.

Your computer or ECU (electronic control unit) won’t be permanently harmed if you disconnect your car’s battery, but it can have some unfavorable consequences. These include forgetting the optimal fuel/air mixture for your car, memorized shift points, and previously programmed radio stations. The anti-theft system in your automobile could also lock you out of the vehicle.

Stay with us though, there’s still a lot more to learn about your computer and car batteries. In this tutorial, we’ll go over the right way to unplug the battery every time. We’ll also go over a quick way to restart the computer without all of that hassle.

Let us first state that we hope you find the links provided here beneficial before you continue reading. We may receive a commission if you buy something after clicking on one of the links on this page, so thank you!

Last but not least, please remember that this content is solely meant for your entertainment and knowledge. We are not attempting to replace your mechanic; rather, we want to help you comprehend what they are doing. You shouldn’t do this at home if you lack the necessary background. You would put yourself and your car in danger in addition to your car.

Will transmission reset if battery is disconnected?

It’s possible that you’ll need to reset your car’s transmission at some point. Fortunately, most of the time, resetting the transmission control module is a simple procedure that practically anyone can complete. We can address your query on whether or not disconnecting the battery will achieve this. We have investigated the procedure so that you would understand it clearly.

On the majority of models of automobiles, simply disconnecting the battery will not reset the transmission. To reset the transmission, you must do a few additional actions after removing the battery.

We’ll go over the procedures in more detail now that we know that unplugging the battery can reset the transmission. You might also be wondering if the transmission is impacted by the battery or if everything is reset when the battery is disconnected from the automobile. Continue reading this page to see what our study has shown to provide the answers to these and other concerns.

Which terminal should I unplug to preserve the battery?

You’ll need to remove the plastic caps that are covering some battery terminals.

The negative battery terminal often has a black cap and a minus (-) symbol on it. The plus (+) sign and a red cap are often found on the positive terminal.

Always take off the negative connection (negative clamp) from the negative terminal before unplugging a car battery. To prevent electric shocks or sparks, do this.

To loosen the connecting bolt, position the socket wrench over it (it’s often approximately 10mm in size), turn it left (counterclockwise), and then tighten.

Release the negative connector and negative battery cable, then take them off and set them aside far from the positive terminal and battery.

How do I detach the proper battery cable to reset the engine light?

  • OFFSET the ignition.
  • Determine which battery terminal is the negative one; it is typically identified by a black cap and the negative (-) sign.
  • After removing the negative terminal bolt with a wrench, remove the negative cable and set it aside.

How long should a battery be disconnected before resetting a car?

Too many people don’t understand what a “computer” in their car is, and even fewer know how to repair one when it malfunctions. The good news is that you can sometimes fix common problems yourself without calling a mechanic or having to wait for them to finish the job.

An example of one of these problems is an engine light, which indicates that your car requires service but perhaps not right away—you should have a professional take a look at it first.

How long does it take to reconnect the battery so that the car’s computer can be reset? You must separate the battery from the vehicle for at least 15 minutes before resetting the computer. Most sources advise leaving the battery off for at least 15 minutes to ensure the computer forgets the code before you reconnect it because some of the electrical currents are retained in the computer for some time afterward.

But hold on, you need to learn more about the computer and battery in your car. We’ll cover how to disconnect the battery in this article. We will also go over how to reset it quickly and easily.

You should like reading this content. It is advised to avoid trying at home if you are not a mechanic or have no training in this area. You could endanger yourself and your car if you don’t know what you’re doing.

How far must you travel after unplugging the battery?

Wait at least a week before getting a California smog check if you recently jump-started or replaced the battery in your automobile. The internal emission monitors necessary to pass a smog test are erased when a car’s battery drains or is removed. Once you’ve driven the new battery 100 to 200 miles, you’ll be ready to travel.

Does disabling the battery turn off the airbags?

  • By putting the work clamp close to the weld, the current route is kept short.
  • removing and isolating the cords from both batteries. First, disconnect the negative battery cable.
  • separating the device from the car’s systems as much as you can.
  • keeping cords away from sensors or computers.
  • removing computers or other delicate electrical components before welding if the distance is closer than 300 mm ” (12″).
  • applying a welding blanket to the vehicle’s windshield and other exposed surfaces.”

“Before or during the inspection of the airbags and other SRS components, it is crucial to take specific safety precautions. To avoid unintentional deployment, the restraint mechanism is disabled as part of these safety measures. Even if an airbag appears to have fully deployed, it may still be able to do so again. Commonly, the negative battery cable is disconnected and isolated in order to disable the restraint devices. In order for the system to totally discharge, time must also pass. For instructions on how to disable the restraint system properly, consult the vehicle-specific service literature. It can also be necessary to disable the SRS to safeguard certain sections when welding or performing other types of repairs.”

Can I simply unplug the positive terminal?

Always unplug the negative first, then plug it back in last. Why? If your wrench runs into the chassis, what happens? If you are on the negative battery terminal with both battery terminals attached, all that happens is ground. But if both terminals are connected, your wrench is on the positive terminal, and you make contact with the ground… BE READY FOR SPARKS, FIRE, AND WELDING.

Always detach the negative first to be safe. As already noted, disconnecting any terminal will stop the drain. Another secure method of battery maintenance is a battery tender.

Is it acceptable to simply unplug the negative terminal?

Always disconnect the negative battery connection first to reduce the possibility of sparks that could harm the electronics in your car or cause a battery explosion. After locating the negative terminal, use the wrench to remove the nut holding it in place. The wrench should be turned the other way around.

If you know how to detach automobile batteries without tools, which requires gently wriggling off the cables, you can continue with your hands once it is liberated. Put on gloves before you remove the nut. The same steps still apply if your car has two batteries, but you’ll need to unplug the jumper cable after removing the negative terminal.

In any case, you must only disconnect the negative terminal of the automobile battery if you are working on the electrical system. There is no requirement to cut both cords.