You should leave your car’s battery disconnected for a minimum of fifteen minutes and no longer than thirty minutes to reset an ECU. To disconnect a car battery, remove the negative power cable from the negative terminal of your car battery with the use of a socket or monkey wrench.
Table of Contents
Do I need to reprogram my BMW after changing the battery?
Apart from the registration procedure, you also have to code your BMW computer. It’ll be necessary each time you replace your battery, no matter its specifications – whether your battery is similar or extremely different from your old one.
How do I reboot my computer after replacing my BMW battery?
- First of all, turn the ignition key of the BMW car to the accessory position once the lights and radio are on. You have to do this before starting the vehicle.
- Again, press the “Trip” button and hold until Reset appears.
- Then, press the same button for the third time.
Do I need to reset the ECU after replacing the battery?
Most ECUs are self-learning and should reset themselves after learning that a new battery has been installed. If you’re stuck, go to a mechanic for diagnostic assistance.
How long does it take for a BMW computer to reset?
You can reset a BMW ECU by unplugging the negative battery cable for 10 to 15 minutes. This should be enough to reset the ECU in most BMW models. If this doesn’t work, you can also try jumpstarting your car to reset it. This will also help if the issue is a drained battery!
How do I reset my BMW computer?

How do I reprogram my car after changing the battery?
- Detach the battery cable for two to three minutes.
- Reconnect the battery and start the car.
- Drive the car for at least 10 miles to let the engine control units find any potential problems.
Do I need to program my car after changing the battery?
Typically, you do not need to reprogram the key fob after changing the battery. However, if you’ve replaced not just the batteries but also some of the internal wiring and electronics, you may need to reprogram it by pairing it with your vehicle once again.
How long does it take for a car computer to reset itself?
So why is the light still on? Here’s something you probably don’t know: after clearing the car’s computer you will need to drive for about 50 to 100 miles. As you drive your car the computer will monitor all the sensors and register the results.
How do I reset my ECU manually?

Will unplugging battery reset ECU?
It depends on the car’s age and type of ECU used. On some older cars, disconnecting the battery will reset the system but in most new cars it does nothing, except potentially reset the clock and radio station presets.
How do I manually reset my car computer?

How do I reset my BMW 335i computer?
- Turn the key to the ON position without starting the vehicle.
- Press and HOLD the ODOMETER button for TEN seconds.
- You will see FGSTNR with a number on the dash screen.
- Add the last FOUR numbers.
How far do I need to drive my car to reset the computer?
In general, you will need to drive between 50-100 miles after you clear your car’s computer. Hopefully, this will get rid of the check engine light once and for all. If it doesn’t, there may be a more critical factor causing this item to turn on.
How do I get my BMW out of theft mode?
Look for a button that allows you to slide the physical key out of the fob. Step 2: Turn the vehicle key to unlock the car door without releasing it. Hold the key for 30 seconds in this position. This will signal to your car’s system that you have the right key, and will enable you to bypass your car’s alarm system.
How do I reset my BMW 3 Series system?

How do I factory reset my ECM?

What will resetting ECU do?
“Resetting the ECU” is the process of clearing all the long term memory from the ECU’s memory. These variables trim idle speed, fuel, spark, and more. The ECU will also store trouble codes for diagnostic capability.
What happens if BMW battery is not registered?

Does disconnecting your battery reset the codes?
Disconnecting the battery will not clear any codes in memory of the computer for stored OBD2 codes. The only way to clear the codes is to use a scanner and use the code clear function.
How do I reset my BMW by disconnecting the battery?

Does the ECU need to be reset?
Resetting your ECU is a popular myth. In reality, resetting your engine control unit (ECU) after modifying your engine isn’t necessary. However, resetting your ECU can help you fix a faulty check engine light or restore your car to factory setting.
Will disconnecting car battery harm computer?
Disconnecting or replacing a battery on a computer-equipped vehicle may cause starting, driveability and a number of other problems, including loss of air conditioning, power accessory functions (door windows, seats, sunroof), false warning lights, even damage to certain electronic modules!
Can Autozone reset my car computer?
Yes. Almost every code reader has the ability to erase codes. Keep in mind, on some vehicles, when you erase codes, you are also erasing information that can help a mechanic with diagnosing the cause of the check engine light/code.
Can Autozone reset computer?
Option A: Go to Autozone The answer is yes, butโฆ there are a couple things to remember: Local auto parts stores will typically offer to read your codes for free, but not all locations will clear the light due to liability issues. Some of them don’t even carry code readers that can reset the check engine light.