Will removing the negative battery cable reset computer?

While disconnecting the battery will not permanently damage your vehicle's computer, it can cause it to function differently. That's because, if you disconnect your battery for long enough to reset the computer, it may cause the processor to forget everything it has learned.
Takedown request   |   View complete answer on vehq.com


What happens when you disconnect the negative battery cable?

If you remove the negative clamp and inadvertently complete a circuit to ground, there will be no current flow because the ground clamp is already grounded. Subsequent shorting of the positive terminal to ground will then produce no current flow because the current has no return path to the negative post.
Takedown request   |   View complete answer on popularmechanics.com


Will unplugging the battery reset ECU?

A. 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.
Takedown request   |   View complete answer on drive.com.au


Is it OK to just disconnect the negative terminal?

Disconnect battery negative cable

It is a good practice to always disconnect your negative battery terminal first, to minimize the risk of sparks that can lead to car electronics damage and battery explosion. Once you have located the negative terminal, use the wrench to free the nut that tightens the terminal.
Takedown request   |   View complete answer on rxmechanic.com


Why do you remove negative terminal first?

Negative first

It's important to disconnect the negative side of the battery first, otherwise you can cause an electrical short if the positive is removed first.
Takedown request   |   View complete answer on mcmgarage.co.uk


Doing This Will Reset Your Car and Fix It for Free



Do I disconnect the positive or negative to check the alternator?

You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.
Takedown request   |   View complete answer on yourmechanic.com


How long should I leave the battery disconnected to reset ECU?

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.
Takedown request   |   View complete answer on mycarmakesnoise.com


Does disconnecting battery reset tune?

And removing your battery cables for safety precaution's doesn't remove the tune . It will reset everything as far as your air/fuel ratio so when you start it up again and let it do the idle adjustment .
Takedown request   |   View complete answer on focusfanatics.com


Will disconnecting battery reset BCM?

To complete the body control module reset, you will have to reconnect the battery. This reestablishes the electrical supply through the BCM as well as other electrical peripherals of the vehicle.
Takedown request   |   View complete answer on motorverso.com


How long does it take for a car computer to reset?

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. You can use GOFAR to constantly monitor your car diagnostics.
Takedown request   |   View complete answer on gofar.co


Do you have to reset car computer after replacing 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.
Takedown request   |   View complete answer on getjerry.com


How do you reset the PCM?

In order to perform a PCM hard reset: Press and hold the PCM Info button for approximately 10 seconds until the PCM reboots.
Takedown request   |   View complete answer on porscheenglewood.com


What does a hard reset do to your vehicle?

By doing a hard reset, you're essentially wiping the slate clean. After you've done this, proceed to scan the vehicle and search for any faults. If there is a hard code it'll either return immediately or after driving it for a few miles or so.
Takedown request   |   View complete answer on motorhills.com


Will disconnecting battery reset crankshaft sensor?

To reset the check engine light you can disconnect the battery via the negative battery terminal and let the vehicle sit for an hour before reconnecting the battery. This will drain all of the power from the electronics and clear any short term memory.
Takedown request   |   View complete answer on yourmechanic.com


Is it OK to just disconnect the positive terminal?

Be safe: always disconnect negative first. Disconnected either terminal will prevent drain, as stated already. A battery tender is another safe way to maintain the battery.
Takedown request   |   View complete answer on focusrs.org


How do you check if alternator is working by disconnecting the battery?

If you're tempted to test an alternator by disconnecting the negative battery cable, don't do it. A good alternator may indeed keep the engine running without the negative cable, but this was never a good test. In the pre-computer days, you could pull it off without damaging anything.
Takedown request   |   View complete answer on familyhandyman.com


Which terminal do you take off to check your alternator?

Step 5: Test the Alternator With the Engine Off
  1. Turn the engine off.
  2. Turn on your voltage meter and set it to DC volts.
  3. Connect the positive lead to the positive terminal (+) on the battery, then connect the negative lead to the negative terminal (-) on the battery.
  4. Check the battery voltage on the voltage meter.
Takedown request   |   View complete answer on instructables.com


Which battery terminal must be disconnected first and why?

Disconnect the negative terminal of the battery

You should always remove the negative battery terminal first, to reduce the risk of sparks which can make the car battery explode. Once the negative terminal has been located, use the wrench to loosen the nut that holds the terminal.
Takedown request   |   View complete answer on mechanicbase.com


Which terminal do I disconnect to save battery?

If you plan on storing a vehicle for an extended period, it's advisable to disconnect at least the negative terminal from your car battery. This prevents unnecessary battery drain, as a fully charged battery can hold its charge for 6-12 months if you do this.
Takedown request   |   View complete answer on repairsmith.com


Should battery Disconnect be on positive or negative?

The negative cable connects to the body ground already—so there's no additional danger if it rubs. It's the same principle as why you should always disconnect the battery's negative side first before performing electrical service.
Takedown request   |   View complete answer on motortrend.com


Will a car computer reset itself?

Will Check engine light reset itself? Your car's check engine light will reset itself after you repair the problem in most car models. But it may take some time. A car usually needs 10-20 successful cycles before it will reset the check engine light by itself.
Takedown request   |   View complete answer on mechanicbase.com


Does disconnecting car battery clear codes?

Disconnecting the battery will clear the error codes and reset the check engine light.
Takedown request   |   View complete answer on wikihow.com
Next question
What is a luxe item?