Quick Answer: Can You Clear Trouble Codes By Disconnecting Battery?

Can you clear codes by disconnecting battery?

The battery disconnect method will work on most vehicles.

Some late model vehicles will not clear trouble codes by disconnecting the battery.

On these vehicles trouble codes are stored in the ECM’s ROM, and only a scan tool will clear trouble code(s) and turn off the check engine or malfunction indicator lamp (MIL)..

What happens if you disconnect the positive terminal first?

It can fall across either terminal and the car and nothing will happen. If you disconnect the positive terminal first and you drop a spanner, it is possible for it to fall across the positive terminal and any earth on the car, with spectacular and possible dangerous results.

What does clearing fault codes do?

Clearing a particular code on the other hand simply tells the system “forget that failure happened and turn off the check engine light.” Not the same thing. On a 93 though the ECU may not be quite that capable. Code comes back after a while.

What happens if you don’t disconnect the negative battery cable?

Never disconnect a battery cable when the engine is running. If the tool touches the battery positive terminal and a chassis ground simultaneously, as long as the negative battery cable is not connected, no damage will occur.

Can disconnecting battery reset ECU?

Will disconnecting battery reset ECU? Can a ECU be reset? Yes, all ECU (Engine Control units) can be reset and be should reset once per manufacturer’s guideline for a smooth relearn process or upon installing a replacement unit.

Can I just disconnect positive terminal?

Just be careful and ALWAYS disconnect the POSITIVE terminal first. Keep the battery grounded (negative is ground). Try not to touch the positive wire on metal as it possibly could be holding some charge after you disconnect it.

Is it OK to just disconnect the negative terminal?

“If someone is going away for a few months over the winter, they should definitely disconnect the battery. It’s the only way to prevent battery drain,” Rashidi said. … I would recommend taking the negative battery post out, and wrapping something around the end so it doesn’t touch anything while you’re not there.”

Can you tell if codes have been cleared?

There really i no way of knowing if codes have been cleared. If you get lucky and have a good scanner, (Modis, Autel, etc.) you may be able to locate history codes. If you are looking to purchase a vehicle, ask the seller to allow you to road test the vehicle.

Is it illegal to clear check engine codes?

It’s called fraudulent concealment and it is illegal. Many states will allow punitive damages. This car dealership should count themselves lucky that you discovered this problem before it caused any personal injuries.

How long do you leave battery disconnected to reset ECU?

Disconnect both positive and negative cables from the battery, then touch positive and negative connectors for 30 seconds, that will do it.Log in.Full Site.Top.

Can you reset check engine light without disconnecting battery?

Switching the ignition on and off is also one of the methods of hard reset without disconnecting batteries. Put the keys in your ignition and turn your ignition on and off consecutively after a span of a second in each step. Once it is done, see if the engine check light is still coming on or not.

What happens if you unplug the ECU?

However, if the ECU is unplugged, it will retain any charge it may have even if you create a power draw someplace else in the vehicle. So you’d need to wait a decent amount of time to be “sure” it’s drained. Some folks go so far as to unplug the battery and let the car sit over night.

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

The readiness monitors will remain until the car has been driven long enough for the computer to evaluate the various system and sensors. The amount of time can vary based on the vehicle. In some cases it can take up to 100 miles for all of the computer monitors to completely reset.

How long do I have to drive my car to reset the computer?

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.

Is it OK to clear engine codes?

If your main reason for buying an inexpensive scanner is to reset the check-engine light, know this: clearing the code and turning the light off doesn’t mean your issue has gone away. … It’s possible that the warning light won’t come back on after you clear the code.