Motorcycle Alarm Going Off? (7 Common Causes)

Whether your motorcycle alarm is going off in the night and waking up the neighbors, going off whilst riding or just going off when it shouldn’t be – we’ve got you covered…

In this article we’ll go over the most common reasons why your motorcycle alarm keeps going off.

Here is the short answer to why your motorcycle alarm keeps going off:

The most common reasons your motorcycle alarm keeps going off are a dying battery, low key fob battery, key fob faults and wiring and electrical issues. Another common cause is the alarm itself is faulty or has been badly installed.

1) Motorcycle Battery is Weak or Expired

A dead or expired motorcycle battery can cause a slew of wiring, running, and starting problems with your motorcycle, including randomly setting off your bike alarm.

  • Bike batteries typically have shelf lives of between 2 and 5 years.
  • Start off by inspecting the terminals
  • Sometimes just tightening them is enough to solve the problem. 
  • In other cases, the terminals are dirty or contaminated with rust.
  • In which case, use a simple baking soda and water mix, and clean the terminals free of corrosion

If this hasn’t worked, you’ll need to test the battery with a multimeter…

How to Test the Battery

  • Before testing, remove the surface charge from the battery, this allows for an accurate reading.
  • Simply turn on the headlights for 2 minutes then turn off.
  • Set the multimeter dial to the ’20 Volts’ setting.
  • Make sure the bike is turned OFF

The multimeter will have a red probe and a black probe:

  • The red probe is for making contact with the positive terminal
  • The black probe is for making contact with the negative terminal.

Measure across the battery terminals.

As a general rule anything between 12.6V and 12.06V, the battery needs to be charged to get it to 12.73V or more.

Anything less than 12.06, you can try charging the battery but it might already be toast.

2) Problematic Key Fob

Another common reason a motorcycle alarm goes off is due to the key fob, whether the fob itself is faulty or the fob’s battery is about to die.

Many of the motos on today’s market come equipped with a keyless fob that allows the bike to start up, providing the fob is in range of the vehicle. If the batteries are weak, or if the fob is damaged or faulty, the bike’s ECU won’t detect the key fob is in range, and mounting the motorcycle may trip the alarm.

Bikes that come stock with a built-in alarm and fob system often allow the riders to set an emergency bypass pin code that will override the alarm in the case of an absent fob.

This code will come in handy if the battery in your fob starts to weaken.

  • If you suspect the key fob is why your motorcycle won’t start, start by replacing the fob battery.
  • Sometimes, cleaning the inside of your key fob is enough to solve the issue.
  • Failing that, the fob itself may be damaged.
  • Take your bike to the dealership; in some cases, they can reset or flash the fob and fix it; in others, they’ll have to program a new fob for you.

Tip: Refrain from storing your fob in the same pocket as metal tidbits, like loose change, hardware, keys, etc. Nor should you store your fob alongside anything electrical, including other fobs. This can cause interference with the communication between the ECU and the key fob, meaning your bike won’t sense your fob, so your motorcycle alarm sets off for no reason.

 Some bike manuals offer key fob and pin-code reset instructions.

That said, if you’re not the original owner of the bike and don’t know the factory or previous owner’s codes, you might have to swing by the dealership with your proof of purchase to have it reset for you.

We suggest you refrain from storing your fob on your motorcycle, especially if you find your fob’s battery dies faster than usual.

Not only does this increase the risk of theft, but it also keeps the fob in constant communication with your bike’s ECU 24/7. This eventually kills the fob battery, causing the alarm to turn on although the fob is close by.

3) Sensor Interference or Damage

Some modern touring bikes equip sensors that alert the rider if the bike’s hard bags or touring trunk are opened. 

Suppose these simple electrical sensor switches get contaminated by grime, dirt, moisture, or food/drink spillage. In that case, they may fail to communicate accurately with its counterpart when the cases are all closed.

On other bikes, similar sensors tell the bike when the fob is present if someone is sitting in the seat, etc.

If any of the bike’s sensors are dirty, contaminated or malfunctioning, this can be enough to cause the alarm to go off.

Some bikes with sensor issues will alert their riders with incorrect messages, like the lean angle warning or an alert that the saddlebags are opened when they’re not.

Even a faulty Turn Signal Security Module was known to cause the alarm to go off without reason on some older Harleys; the problem went away after the TSSMs were upgraded or replaced. 

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4) Electrical Wiring Failures

The motorcycle alarm is an electronic system wired into your bike’s wiring harness.

The wiring harness is the integrated circuitry of the motorcycle, all the pathways through which electricity travels from the battery to the various electrical components.

For the past 35+ years, most bikes have circuitry that an Electronic Control Unit or ECU regulates.

All your bike’s electrical pathways are integrated to be governed as one united system of smaller systems.

So, a problem elsewhere could be stealing power from or surging it to your alarm system, causing erratic behavior.

If any of your motorcycle wires are damaged, frayed, burnt out, crossed, or if any of your fuses are blown, erratic electrical flow could be why your motorcycle’s alarm keeps going off.

Blown fuses are usually a blessing in disguise, as fuses are designed to blow when there is excessive electrical current in order to prevent damage to circuitry and components.

Still, the burnt-out fuse must be replaced promptly to restore your bike’s electrical flow to working order.

If damaged wiring is why your motorcycle’s alarm goes off randomly, it will need to be replaced before the bike is ridden.

Damaged wires can cause blown fuses and power surges which have negative consequences for your bike.

5) Faulty Electronic Control Unit

If your bike’s ECU (Electronic Control Unit) is compromised by damage, overheating, corrosion, bad or missing updates, or aftermarket flashing, your motorcycle alarm may come on randomly.

If you suspect this is the cause, it’s essential to start by ensuring the battery, the source of your ECU’s power, is in a healthy condition and that the ECU is receiving the required voltage.

It’s not typical for an ECU that hasn’t been tampered with to fail, but it does happen.

Your ECU governs everything from engine performance to ignition sequencing to lights and displays.

Therefore, if a problematic ECU is a reason your bike alarm keeps going off, you’ll likely notice erratic behavior with other systems too.

6) Water Ingress

Some motorcycles aren’t great when they get wet, whether it’s washing them or riding in the rain, the water ingress can wreak havok on a bikes electronics.

On some models, water can get into the main connector for the alarm, which can often be located under the tank – that sets it off.

Similarly, water can get into the plug/socket for the ignition barrel which will often be located near the left fork leg – which can set off the ignition tamper alarm.

It’s a bit of a pain, but you’ll need to need to weatherproof these connectors, otherwise the alarm will go off every time you wash it.

7) Aftermarket Installation Problems

If you or a private mechanic installed your aftermarket, non-OEM alarm system and your motorcycle alarm set itself off for no reason, it may be due to a loose hook up, crossed wire, or skipped sensor.

If you did the installation yourself, work through the installation manual and double-check everything.

Also, remember that not all aftermarket alarms are compatible with every bike.

While increasingly modern motorcycles are coming stock with alarms, that hasn’t always been the case.

It used to be that motorcycle alarms had to be installed by the owner or a mechanic. Not all alarm systems are created equally, and not all installations are done the first time correctly.

Some aftermarket alarm systems strain the battery to the point of shortening its life. If the alarm senses the draining battery, it’s set to assume that someone is tampering with your bike’s power supply and triggers the alarm to alert you.

The problem here manifests as a loop:

  1.  The bike alarm drains your battery because your bike specs don’t account for the additional power usage of the new alarm.
  2. Your alarm senses the drain on your battery, unaware that it is the cause of the drain.
  3. Your motorcycle alarm starts going off as a response to the power loss.
  4. The cycle repeats until your bike battery is dead.

To make matters worse, many of the aftermarket alarm systems have a mini battery that’s being charged by sapping your bike battery. This means that your alarm has enough power to go off on its own even if you unhook it from your battery or if your battery is drained.

If this is your situation, we suggest uninstalling your aftermarket alarm system and using one of the other security methods described below.

Alternative Suggestions

Ground Anchor

A ground anchor is a rugged and secure strap that threads through your wheelbase to lock into bolts installed into the walls or concrete near where you store your bike. This moto-security method isn’t mobile.

Chain and Padlock

This isn’t entirely as secure as the ground anchor, but it’s mobile. You wrap the chain through your rear wheel and lock it so the bike can’t move.

Disc Lock

Latching a disc lock to your motorcycle’s disc brake prevents the motorcycle from moving by locking the brake and, therefore, tire in place. These are the most mobile of the three items on the list, allowing riders to carry one for each wheel without adding too much luggage.

How Do I Disable My Motorcycle Alarm?

You can disable your motorcycle alarm by removing its fuse, disconnecting it from the battery (and disconnecting your mini alarm battery, if applicable), starting your motorcycle, locking and unlocking your touring cases (if applicable), or starting your motorcycle.

Remove Your Alarm System Fuse

Your motorcycle alarm system includes an isolated fuse that protects its wiring circuitry.

If you pull the fuse, the system will shut down as if the fuse is blown to protect the circuit.

This cuts the power to the alarm system without cutting the power to any other part of the bike.

Detach your Battery Terminals

If you’re attempting to disconnect your motorcycle’s battery while the bike is parked, your best bet might be to disconnect your battery altogether.

If you’ve disconnected your bike battery, you’ve also disconnected your bike’s electrical system, including your starter, which means it won’t start until you reconnect its terminals.

Start Your Motorcycle

Unless the problem lies with your ECU or fobs, your alarm should stop going off as soon as you start your engine.

That said, if your fob or your control unit is the issue, one might not sense the other, and the alarm may continue to sound while you’re riding as it assumes your fob isn’t present if it can’t sense it.

Lock and Unlock your Saddle Bags

If your motorcycle alarm keeps going off, try clicking the lock/unlock button a few times.

Even if the fob’s battery is weak, you might luck out and get one to unlock/lock cycle in, and that’s all you need to kill the sounding bike alarm.

Do Motorcycle Alarms Drain the Battery?

While a specialty stock alarm system is designed to work harmoniously with your motorcycle’s battery, a generic aftermarket alarm can pull enough power from your battery to drain it. This draining can happen at a low, sometimes undetectable rate, especially noticeable after a week without riding.

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  • Michael Ta Nous

    I've been weaving words into stories since my early scribbling days, and my journey in the world of motorcycles and their communities spans almost two decades. Living with a talented motorcycle mechanic as a roommate, our garage transformed into a vibrant workshop where I absorbed the intricacies of...