Which battery cable do I disconnect to reset engine light?

Steps to Reset an Engine Light

Locate the negative terminal on your car battery. It will have a black cap and a negative (–) symbol. Using a wrench, loosen the nut on the negative battery terminal and pull the negative connector from the battery. Keep it disconnected for 30 to 60 seconds.

Can I reset check engine light by unplugging battery?

3) Disconnect the Battery then Reconnect

Ideally, this will clear the data, turning off the light. You can then reconnect the battery and turn the ignition on. After about a minute, the check engine light code should be off.

Which battery cable do I disconnect to reset computer?

The most efficient way to disrupt the ECU's power supply is to disconnect the negative cable from the negative terminal.

Will removing the negative battery cable clear 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.

Is it better to disconnect the positive or negative battery cable?

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.

Fastest Way To Reset A Vehicles Computer, Check Engine Light

Will disconnecting negative terminal reset car?

Like desktop computers and most other electronics, disconnecting the battery cable for a short period will not fully reset your ECU due to the residual power remaining in the circuits.

What happens if I remove the positive terminal first?

If you disconnect the positive terminal first, one slip of your wrench could send a direct short to the ground, which can be very dangerous. Its possible that you could experience a huge spark, the wrench could melt in your hand or the battery could even explode!

What happens if I remove negative cable from car battery?

The negative () cable is the ground cable; it is always connected to the frame or body metal and can safely be disconnected first with no chance of causing sparks. By the same token, always reconnect the positive cable before connecting the negative cable.

What happens if you disconnect the positive terminal while car is running?

HOWEVER, be aware that this test is not without risk to damaged car electronics. If your alternator is malfunctioning by over-charging your battery, disconnecting it may allow the alternator to provide an even higher voltage to the car electronics, and potentially damage those sensitive components.

Do I need to disconnect both battery terminals?

Disconnect Battery Cables

Your job is to disconnect both. However, DO NOT disconnect the positive terminal before the negative one. Doing so can cause an electrical short. Always disconnect the negative battery terminal first.

How long do I need to disconnect battery to reset computer?

How long does battery need to be disconnected to reset ECU? At least 5 minutes or quicker if you disconnect both terminals and hold them together. Make sure that nothing touches the battery terminals.

What happens if I disconnect the negative battery terminal?

Will the Car Battery Drain if the Negative Cable Is Disconnected? A car battery will self-discharge at a rate of 5-15% per month with the negative terminal disconnected. However, the alternative option of leaving the battery connected while it isn't being used will drain at close to 20% per week.

Does touching the battery cables together to reset computer?

See all 2 photos Connecting the positive and negative battery cables together for approximately 5 minutes will drain all of the capacitors in the computers and forces them to cold reboot. This is a very common fix for communication problems.

What does disconnecting the positive battery cable do?

If you disconnect the positive cable first, you might have several adverse effects including: Tools creating an arc of electricity. Shorting out electrical components. Blowing fuses.

Can you manually reset check engine light?

To reset a check engine light without a scanner, disconnect the negative battery cable and wait a few moments. This will reset the diagnostic system in your vehicle, and if the underlying issue has indeed been resolved, the light should go off immediately.

Do you disconnect red or black first?

Always disconnect battery cables exactly in this order; disconnect the BLACK negative cable first, and then disconnect the RED positive cable. Always connect battery cables exactly in this order; connect RED positive cable first, then connect BLACK negative ground cable.

Which battery terminal must be disconnected first and why?

Removal of Old Battery

Remove the negative (-) terminal first. This precaution is necessary to avoid damage to wiring and the battery by accidentally grounding tools. Remove the positive (+) terminal.

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.

When disconnecting a battery What do you disconnect first?

When disconnecting the cables from the old battery, disconnect the negative first, then the positive. Connect the new battery in the reverse order, positive then negative.” When you are replacing your car battery, It isn't always easy to remember the order in which to disconnect and reconnect the terminals.

What happens if you connect negative battery terminal first?

Never connect the black cable to the negative (–) terminal on your dead battery. This is very dangerous, could result in a possible explosion. Make sure you follow the instructions in your owner's manual when jumpstarting your vehicle.

Which terminal should you disconnect first?

Things You Should Know

Disconnect the negative terminal first, then the positive terminal.

What should you not disconnect when disconnecting a car battery?

You should never attempt to disconnect your car's battery while your car is powered on. We'd also recommend using safety equipment, like gloves and safety goggles, if you have them on hand.