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Why Is My Car Amplifier Staying in Protection Mode?

Protection Mode means that the car amplifier has entered a protection state. In other words, it protects itself and other car audio elements from further damages.

But, “Why is my car amplifier staying in protection mode?” This is the question many car audio enthusiasts are asking, so let’s find out why.

In general, car amplifiers stay in protection mode even after completely turning off the car audio system because car amplifiers need some time to cool down before they can be turned on again. Another cause of car amp staying in protection mode could be an internal malfunction of the car amplifier.

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Tip: Although there are many causes for the amplifier to stay in protect mode, incorrect wiring is the most common problem. When installing an amplifier, make sure it has both power and ground good quality wires with the same gauge.

I have been using KnuKonceptz wires for both power and speakers for a long time, and I am happy with their quality and flexibility.

In this article, I will provide car stereo users information on how car amplifiers work, when they go into protection mode, and how to fix this.

What Does It Mean “Amplifier in Protection” Mode?

When the car amplifier is in protection mode, it means the car audio system is not working, and in the best case, the sound is distorted.

Protection mode is caused by speaker short circuits, amplifier internal short circuit, or car battery voltage getting too high (or low). 

Amplifier protection modes are designed to protect your car audio system from damage due to overload, short circuits, or overheating of the car audio system.

However, very few people know what it takes for an amplifier to enter protection mode, and even fewer can properly troubleshoot car amplifier issues that might help prevent car amplifiers from staying in protection mode.

What Causes an Amplifier to Go Into Protection Mode?

Several things might cause car amplifiers to enter protection mode:

1) car battery voltage gets too high (or low).

2) car amplifier receiving too low of an audio signal.

3) car amplifier is being overloaded with power consumption.

4) car receiver or car head unit is sending a wrong input signal to the car amplifier. For example, a faulty RCA cable can cause this.

5) car amplifier overheating. This is more common if a car amp is too small for the audio set-up or if there’s not enough ventilation surrounding the car audio system.

6) Short circuit in car wiring or speaker.

7) Connecting speakers with an impedance that is larger than the car amplifier’s RMS power rating.

All of that sounds scary, but in reality, most times, when a car amp goes into protection mode, it is due to power consumption issues and overloads.

Especially if you have just installed new speakers and they draw more power from the battery than your old speakers, your amplifier may start to malfunction.

Why Does My Amp Go Into Protection Mode When Bass Hits?

Large and powerful car subwoofers often cause car amps to go into protection mode.

This is especially notable when you have a strong subwoofer and amplifier that does not have much more power than the subwoofer will need, or worse when it actually is weaker than the subwoofer.

When the car amp is turned on, it monitors power consumption and current draw from the battery.

If the car amp detects that power is being drawn faster than the battery can keep up (which means that the car amplifier is drawing more power than your car’s electrical system can send through), the car amp will shut down.

If your amplifier can successfully manage spikes with increased power demands, your car stereo will play louder and sound better at higher volumes without shutting down or turning into protection mode.

However, some car amps, especially those cheaper from the bottom shelf, may not give us this kind of luxury, and they’ll shut down instead when we try to turn them up. This is called “overloading,” or overdriving an amplifier.

Why Amp Goes Into Protect Mode When RCA Is Plugged In?

It’s usually not a problem to connect RCA cables straight to the car stereo. They usually work without any issues until the car amp turns into protection mode.

If the amplifier goes into protect with the RCAs plugged in, there could be a problem with either connection or internal in the amplifier itself.

First, you need to check the RCA shields in the head unit. If the shield ground of the head unit is OK, then the amplifier could be an issue.

You need to power up the amplifier and measure the voltage on the RCA jacks, and to do the test, you need a multimeter. First, touch the black probe to the ground terminal of the amp and then the red probe to each of the RCA shields.

If the display shows 10V or more, the amplifier may have a shorted transformer. On the other hand, the transformer works fine if the display indicates much less voltage, like 1V.

Some budget amplifiers have a problem with broken connections between the RCA shield and the circuit board, meaning that the shield is directly connected to the NON-bridging speaker terminals.

If you have this in your amplifier, it sometimes helps to turn the RCAs left and right to ensure the connection is solid.

How to Get My Amp Out of Protection Mode?

If your car amplifier stays in protection mode after being turned off, you have a problem.

To get the amplifier out of the protection mode, you have to check the entire system.

The first is to check and replace any blown fuses and cool down the car amplifier to normal operating temperatures before it resets itself.

It is also important to make sure that the amplifier has a solid connection with the battery and all speakers are correctly wired. To prevent any temperature issues within the wires or connections, you can use wires with a lower gauge rating.

How to Reset Car Amplifier From the Protection Mode?

When you check the whole system, and there is no damage, all wires have a solid connection, and all amplifier settings are correct, you can reset the car amplifier from the protection mode.

To do this, you need to disconnect the amplifier from the car battery. First, unscrew the positive wire from the amplifier terminal (often red or blue) and keep it disconnected for few minutes.

Although the amplifier should reset as soon as you remove the power source, it is better to disconnect the car battery for a minimum of few minutes or for longer and let the amplifier completely cool down and reset the electronics.

Some amplifiers have internal memory, so disconnecting them for just a few seconds may not reset them.

How Do I Stop My Amp From Going Into Protection Mode?

Although an amplifier is an electronic piece of equipment and can get damaged for many reasons, there are few steps you can take to prevent the amplifier from going to the protection mode.

Solid Connection of Power and Ground Wires

Make sure the power and ground wires are not loose, which could cause intermittent connection and would force the amp into protect mode. The proper solution for this is to make sure your power and ground wire are firmly secure on both ends.

First, check the connection on your amp, make sure it’s solid, and check the other end for the power wire. You want to have all connections tightly fastened into the fuse to the positive terminal on the car’s battery.

For the ground wire, make sure it’s tightly fastened to the exposed metal on the car’s chassis. All paint in the connection point should be removed by steel brush or sanded away, so the ground wire has a clean connection with the car’s chassis.

Matching Impedance Between Speakers and Amplifier

After you’ve checked both the power and the ground wire and you’re satisfied with the connection points, the second thing you want to check when your amp goes into protect mode is to take your system and make sure it’s compatible with itself. What does it mean?

Take the model number of your subwoofers, the number of subwoofers you’re using, the model number of your amplifiers, and you’re going to check how you have all this wired together.

The important thing is to make sure the speakers and woofers match the final impedance going from the amplifier.

For example, if you have two DVC 2 ohm subwoofers wired in parallel down to a half ohm load and that is wired to a 2-ohm stable mono amplifier, the amp will be running extremely hot.

That amount of heat will build-up, and the thermal protection will kick in, so if your amp is going into protect mode after playing music for a couple of minutes, check the total impedance and make sure it is compatible with the amplifier.

You can double-check this with a multimeter if you have it.

Not Sufficient Ventilation

Another thing to check is the amount of ventilation around the amplifier. For example, if you have it under the seat of a car, it might be building up the heat because it does not have enough fresh air around.

The amplifier should always have enough ventilation to cool itself down, especially if you have installed one in class “A” or “A/B” that produces a large amount of heat.

Speaker Wires Touching Each Other

Another common reason your amp might go into protect mode is if the positive and negative speaker wire running from your amp to your speakers touch each other either at either speaker or amp terminals.

This issue can also happen if you have a subwoofer in an enclosure box and the speaker wires are touching each other in the enclosure box terminals.

To fix this problem, make sure the wires do not have any loose strands or use the proper wire connectors.

Reverse Polarity

One more common issue to prevent that can happen due to the wrong installation is the installation error is the reverse polarity.

The opposite polarity of the power and ground wires can be devastating to the entire car audio system.

Reverse polarity means your power and your ground wires are in the wrong place and essentially backward, so you have your power wire going into your ground terminal and your ground wire going into your power terminal.

It is easy to avoid this. Just always double or even triple-check your work after you’ve done an installation.

Make sure that the positive wire is connected to the positive terminals and the negative wire to the negative terminals.

This check is crucial because this can lead to permanent failure of your system.

Blown Speakers

Another thing that can cause your amp to go into protect mode is a blown speaker.

An easy way to check this is to take a multimeter, check the impedance at each terminal on your speaker, and make sure it’s up to specs. If you don’t have a multimeter, you can use a 9V battery instead.

To test the speaker with a 9V battery, take a speaker wire and run it out of the positive terminal on your speaker the positive terminal on your 9V battery.

Then take another speaker wire and run it from the negative terminal on your speaker to the negative terminal on your battery.

If the speaker makes a pop sound and you notice the cone goes up, you know that that voice coil is good.

If there’s no movement on the speaker when you do this test, it can mean that a speaker can be blown, and that also can put your amp in protect mode.

Remote Wire Correctly Connected

The last wire you need to check to make sure it’s working correctly is the remote wire.

If you connect the remote wire to the proper place on your amplifier but not on the wrong place on your head unit, or your receiver, it could cause your amp to go into protect mode.

Like with power and ground wire, make sure the remote wire is running to the correct place on the head unit and that there is no intermittent connection.

Battery Voltage

One thing you’ll definitely want to check if your amp is going into protect mode intermittently is the voltage of your car battery.

Typically a healthy car battery will show a voltage of 12.6V, and in most cases, amps have an operating range of around 10 to 16V.

The operating range is specific for each amplifier, so double-check if the amplifier does not activate either low voltage or over-voltage protection. 

Such protection level will set the amp into a protect mode if the voltage drops or goes above the amp’s operating range.

The solution for this is pretty simple. You can test your car battery with the multimeter to ensure it’s healthy and delivers a voltage within your amps operating range.

Correct Gauge of the Power and Ground Wires

The last thing is to check if the power and ground wire have the correct gauge for your system.

It actually should be the first thing to check because if power and ground wire are not thick enough, the amp can go into protect mode to protect itself from unsafe signals.

If you use too small of a gauge wire for the amplifier, the wire will get hot because it might not carry the maximum current the amp needs.

It also may burn up, and a result of this would be a severe voltage drop at the terminals, which could cause the amp to go into protect mode intermittently.

Always make sure that your wires are to spec and matching the power requirements of the rest of your system.


After reading this article, car amplifier protection mode should be a little clearer.

Both issues can be fixed quickly, whether the car amp is in protect mode due to an unsafe signal or some other problem with power and ground wire.

All that needs to happen is that you have to use the correct gauge wire and power wire. This alone will solve any problem with the car amp going into protect mode.