Reset check engine light

When it comes to the reset check engine light process, there are not as many options today as there used to be. Before the invention of OBD 2 resetting your check engine light was a simple matter of disconnecting your battery.

OBD 2 was deployed in 1996. So if your vehicle is newer then that I do not recommend that you disconnect the battery to reset the check engine light. First of all remember if you have a hard failure the light will come right back on.

Another reason for this is that the newer vehicles now have a few installed options in them that require a constant supply of battery voltage. I know what your thinking what if you have to replace the battery. I use a battery tender pluged into the cigar lighter to keep the memory alive.

But stick with me I will explain how to reset check engine lights by disconnecting the battery below on this page. But first it is my dutty to let you know what could go wrong first!

Reset check engine light complications

In most cases, this special code is included in your owner's manual. Or was supplied by the dealer at the time of delivery, which may not do you any good if you have purchased this car used.

Also if your vehicle is equipped with a factory installed car alarm or theft deterrent system disconnecting the battery may cause a few problems with this system as well.

Again, if you have purchased this car new the owner’s manual may provide a procedure for replacing the battery and disabling the alarm system before the battery is disconnected.

And last but not least stored in the computer along with the code is the vehicles learned memory. This stores driving habits like shift points and IAC steps for idle control.

The vehicle may have driveability problems for a while after the battery is reconected. It will recover and re-learn but it may take several drive cycles.

An easier way to clear the check engine light codes is to use an auto scan tool. The automotive scanner will retrieve the codes and clear or reset the check engine light without disconnecting the battery or causing any of the above problems.

The #1 best selling automotive scanner on Amazon is the actron. Click on the product and take a look at the 114 customer reviews on this item.

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Reset check engine light the hard way

Most vehicles from 1996 and newer have a stay alive memory built-in to the computer system. When you disconnect the battery from the vehicle to reset the check engine light. The computer will be able to hold the memory and the code for several minutes and in some cases several hours.

Battery voltage is stored in a capacitor and is supplied to the computer to keep the memory alive. The way around this is to disconnect the battery and hold down on the horn to drain the small electrical current that is stored in the control modules capacitor this will reset check engine light.

As a side note, when you do this you will definitely erase all memory associated with the computer. When you reconnect the battery on the vehicle and confirm the reset check engine light procedure has been successful, you may find that the engine idle, may be erratic for several drive cycles.

This is because the memory idle learn has also been erased along with your check engine light code. This problem is usually short-term and will correct itself, after driving the vehicle for a few miles at highway speeds.

Also note if the check engine light comes back on after this reset check engine light procedure you have a hard failure code. This is when a failure is constant and will need diagnosis.

So to review you do have a few options for resetting your check engine light, but the easiest way is to use an auto scan tool to clear the code. To the left is the cheapest scanner on the market. It reads and erases codes only.

This is much better then disconnecting the car battery. Using the automotive scanner tool will avoid any and all of the above-mentioned problems.

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On my auto scan tool homepage you will find a few more articles about the diagnosis of check engine lights. Plus more on the reset check engine light procedure using scan tools


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