A car alarm that is not working at all or not working properly can be extremely annoying to you and your

neighbors. It may also put your vehicle at an increased risk for theft or vandalism. Almost all car
manufactures today provide several anti-theft options on their vehicles, including alarms. Alarms have
proven to be an effective means of deterring potential thieves and vandals. While this is good news for
owners of vehicles with alarms, these alarms, like other electrical components, can go bad.

The following steps will help guide you on how to reset your factory car alarm. While some of these tips
may apply to aftermarket car alarms, it’s best to consult a manual if you are experiencing problems with
your aftermarket alarm.

 Note: Do not attempt any repairs you do not feel comfortable completing on your own. Because
the alarm system draws power from the battery, you should exercise extreme caution when
attempting any repairs.

Method 1 of 5: Resetting the alarm remote

It is possible that the key fob or alarm remote has failed and is not sending a proper signal to your
vehicle’s alarm system. When this happens, your vehicle’s alarm may inadvertently end up going off
without you wanting it to.

Step 1: Consult your manual. On older vehicles, the owner’s manual may provide a way to reset the key
fob or alarm remote.

Most procedures will vary from car to car, but you can try removing and replacing the fob battery.

Step 2: Use a code reader. On newer vehicles, the key fob or alarm remote may need to be reset with
a code reader/scanner.

Your owner’s manual may tell you how to complete this reset, though you may still want to consult a
mechanic before attempting it.

Method 2 of 5: Resetting the alarm

Some of the more common alarm resets involve less-complicated techniques that can be completed in a
matter of minutes.

Step 1: Unlock the car. Sometimes an alarm will deactivate when you try manually locking and unlocking
the car.

When the vehicle notices that the key has been inserted into the lock, the alarm may shut off.

Step 2: Start the car. You may also try turning the car on to reset the alarm.

Step 3: Use key to lock and unlock. Try inserting your key into the door lock and turning the key to the
locked position and then turning the key into the unlock position twice.

This may temporarily disable the vehicle’s alarm while you drive.
Step 4: Hold key in unlock position. You can also try holding the key in the unlock position for two
seconds.

Method 3 of 5: Reset the battery

Resetting the alarm by unplugging your vehicle’s battery can be dangerous so you should use caution
when attempting this method.

Step 1: Find your battery. Open your vehicle’s hood and locate the battery.

Step 2: Remove the negative terminal wire. Use a wrench to loosen the nut of the negative terminal
and remove the wire from the battery.

Step 3: Reattach the wire. After about a minute, reattach the wire.

This should reset all of your electrical systems including those that power the alarm.

 Note: Disconnecting the battery will also cause your radio to forget presets. Be sure to write
them down before removing the battery’s wire.

Method 4 of 5: Replacing the fuse

You may also want to try replacing the fuse that is associated with your vehicle’s alarm.

Step 1: Locate the fuse box. This is typically located under the left side of the steering wheel.

Step 2: Remove the corresponding fuse. Consult your manual to determine which fuse is associated
with your car alarm.

Step 3: Replace the fuse. Replace it with a fuse rated for the same amperage.

Method 5 of 5: Disabling the alarm

If your alarm is causing a constant distraction, going off often and spontaneously, you may want
to disable the alarmcompletely. Be mindful however, that if you disable the alarm, your vehicle will have
one less safety feature. You should consult a mechanic before deciding to completely disable your
alarm.

 Note: Be aware that because some alarm systems work in conjunction with your vehicle’s
ignition, meaning that if you tamper with the alarm, your vehicle may not start.

Step 1: Consult your vehicle’s owner manual. To find the correct wires to disconnect, you should
consult your vehicle’s owner’s manual.

Resources specific to your car may also be available online.

 Warning: You should be sure to disconnect the battery on your car before attempting to remove
any other wires.
Step 2: Remove the the wires connecting siren alarm control unit. By removing the wires connecting
the siren and the alarm’s control unit, you can disable the alarm until it can be fixed permanently.

While faulty car alarms can be very annoying, it is important make sure there are not deeper issues at
work. While these DIY fixes may solve your problem, you should always consult a mechanic if the
solution seems more complicated. If you need a fuse replaced or a new battery installed, have one of
YourMechanic’s certified technicians come to your home or work to do the job for you.
HOW TO RESET A SECURITY SYSTEM
Need to reset the security light alarm in your car? We are a team of ASE certified mechanics
that have created this guide for you to help save you money and get you back on the road. If
the security light is blinking the immobilizer system is enabled and will not allow the car to
start.
WHAT GOES WRONG?
Most cars today have a security system built into the electrical system (BCM - Body control
module) to deter from theft. The problem is it can sometimes stop the person that owns the car
from starting the engine as well. These anti-theft systems can sometimes get the operational
sequence out of sync which makes the system think the car is getting stolen epically after a
repair job. This can sometimes happen when there is no one in the car but the window is rolled
down while the car is locked. Someone will reach their hand inside and unlock any of the doors.
Another common way for the system becoming triggered is to simply disconnect the battery to
install a new unit or if the battery is allowed to go dead and then jump started. These can
sometimes cause an electrical surge triggering the immobilizer system.
HOW DOES IT WORK?
Car alarms are designed to prevent burglary of the car and warn the owner if a theft attempt is
being made. Usually a car alarm will output a high pitched sound when the system is triggered
by vibration, closed or opened trigger switches or sensing of small and fast changes in battery
voltage. Car alarms can also monitor sensors like infrared, microwave, ultrasound or tilting of
the vehicle in the case of unauthorized towing. Some cars have alarm systems which send out
SOS signals to a cell phone number in case of breakdown or theft. Alarm systems are also
incorporated within a navigation system to increase the security of the car. The navigation
system will send out a ping signal so the car can be received.

The security system can also be used to locate the car in large parking lots by using the
conformation chirp on the remote fob. Sometimes a car alarm can give out a false alarm when it
feels vibrations of thunder or a passing truck. Sensors need to be adjusted properly otherwise it
can trigger the device even when a person accidentally touches the automobile as well.
For people who want added security for their cars can have a police tracking system installed
with the help of services like On Star. These systems come with an additional cost which is to be
paid on a regular basis.
Security systems utilize a remote controller (key fob) so a user can disable the alarm from a
distance. The remote control feature is very convenient if the system is triggered by a false
alarm. A key fob can integrate a variety of functions such as a LCD screen option which can
project the image of a part of a vehicle that is under threat by a thief is one example.
CAN I BYPASS MY CAR ALARM?
A simple response to this question is in most cases no. Security systems are designed
throughout the main PCM and BCM which control a major part of the vehicle's operating
system. Until this system is enabled many systems such as fuel and ignition are shut down.
WHAT WE DID
We called name brand dealerships and told the service writer (who sometimes got us a
technician) a car we bought from them is in the parking lot with a mom waiting to pick up her
kids from school with the alarm light flashing and the car wont start, this worked pretty well.
We have noted down their responses. Hopefully you can gather enough information from us
and them to get your car going again. We have noticed popular similarities in almost all cars
which are pretty generic which we have listed below.
SECURITY RESET INSTRUCTIONS
This is a generic alarm immobilizer reset procedure and it applies to most vehicles.
STEP 1: DRIVERS DOOR KEY RESET
Exit the car with all doors closed and the windows rolled up. Also close and any rear doors such
as the trunk, rear hatch and front hood. Lock the car using the drivers side lock and walk away
from the car at least ten feet. Wait for fifteen minutes and unlock the door, this should reset
the security system.

STEP 2: ACTIVATE THE KEY FOB

Many manufactures will not allow the car to start when the panic button has been pushed. Hold
down the panic button for five seconds to reset the immobilizer.

Next, push the lock button two times and wait ten feet away from the car for ten minutes.

Then hit the unlock button on the fob twice this should deactivate the security system which
should be accompanied by exterior lights flashing or an audible horn beep.

Each of these steps should be followed by the cancellation of the security light. If this light is
blinking while you are trying to crank and start the engine the system is not reset.

STEP 3: TURN THE IGNITION ON

Many immobilizer systems need to see the power utilized from each power input delivered
from the ignition switch. Insert the ignition key and turn it to the on position and then attempt
to start the engine (crank over), the engine wont start. With the key still in the run position wait
10 minutes and the security light should blink and then go out. Turn the key off and wait 5
seconds. Repeat these steps for a total for 3, 10 minute cycles. The car is now ready to relearn
the Passlock code the next time the key is used, any trouble codes will clear after 100 c ycles of
the key.

STEP 4: REMOVE THE ALARM FUSE

The alarm fuse is located in the fuse panel of most cars. Using the owner's manual remove the
fuse which will power down the security system. At this point the car will not start, reinsert the
fuse to reactive the system. This is known as a soft reboot of the immobilizer.

STEP 5: DISCONNECT BATTERY

Sometimes the anti theft system can out of sync due to a voltage spike or an operational error.
Start by removing the battery's negative cable and leave it disconnected for five minutes then
reconnect the battery. This will allow the security system to perform a hard reboot and r eset
the alarm protocol to help the immobilizer start working in the proper sequence.

HYUNDAI SECURITY RESET METHOD

Call to the dealer, here is their response: Hit the unlock button on the fob three or fours of
times and press panic button once. Lock and unlock the driver's door using the key.
ACURA AND HONDA SECURITY SYSTEM RESET INFORMATION
Call to the dealer and this was their response: Unlock the car with the key fob then get into the
car and close the door. Insert the key into the ignition and turn the key on and wait for 90
seconds. If that doesn't work raise the hood and disconnect the battery from the negative
terminal. While the key is in the ignition and in the on position reconnect the battery. If there is
the Honda added security box installed at the lower left side of the kick panel turn the ignition
key to the on position. Locate the small button on the box and hold it down for 90 seconds and
the alarm will bypass.
AUDI IMMOBILIZER RESET INSTRUCTIONS
Call to the dealer, this was their response: With the ignition key try to start the vehicle. Exit the
vehicle and lock all door with the windows up, then unlock the doors using the key fob the
engine should start. Disconnect the battery using the negative cable wait one minute and
reconnect.

MW ALARM RESET PROCEDURE

Call to the dealer, the service writer got us one of their technicians to help us and this was his
response: unlock the vehicle with the key fob twice to recognize the key is valid. Push t he panic
button twice to disable the alarm. Roll the windows up and lock the car. Let the car sit for five
minutes while being more than 10 feet away then unlock the car. Do not disconnect the car
battery because the alarm system has a rolling code that may get mixed up when reconnecting
the battery.
DODGE CHRYSLER JEEP ALARM RESET
Call to the dealer, this was their response: Disconnect the battery for one minute and then
reconnect the battery this should reset the immobilizer system. To disarm the alarm sy stem
press the unlock button on the key fob.

CADILLAC CHEVY GMC AND OTHER GM SECURITY RESET

Call to the dealer, this was their response: Exit the vehicle and unlock the car using the key fob.
Insert the key into the outside door handle and turn it right and then left to lock and unlock.
This can be done to either the driver's or passenger door. Insert the ignition key and crank the
engine over. Hold the panic button down to disable the alarm. Push unlock button and try
starting it. If that doesn't work disconnect the car battery by removing the negative cable end.
The pass lock sensor that controls the security system is built into the key tumbler or tumbler
case which reads a chip inside the key. This chip is generally unseen.
On older GM cars two small wires will break near the tumbler which will activate the system. In
this case the tumbler must be repaired or replaced.
FORD LINCOLN MERCURY RESET OF THE IMMOBILIZER SYSTEM
Call to the dealer, this is their response: Hold the panic button on the key fob for 2 seconds.
Close all of the doors and while using the key lock and use the key to unlock the lock the
driver's door. If that doesn't work remove the negative battery cable for 15 seconds and
reconnect.
MERCEDES BENZ ALARM RESET METHOD
Call into the dealer, this is their response: Install the key in the ignition and turn to the unlock
position unlock. Using the key fob hit panic button. Remove the negative battery cable for five
minutes and reconnect.
NISSAN INFINITI SECURITY RESET
Call into the dealer, this is their response: Using the fob hit unlock button. Use the ignition key
to start the car. Use the key to unlock the driver's door. Remove the negative battery cable and
then reconnect.
TOYOTA LEXUS IMMOBILIZER RESET
We called the dealer here is their response: Lock the car and shut all doors, then use the key to
unlock the driver's door. Push and hold down the panic button on the remote. With no one in
the car lock and unlock the car using the key remote. Disconnect the battery and reconnect as a
last resort.

VOLKSWAGEN SECURITY SYSTEM RESET

To deactivate the anti-theft system use the unlock button on the remote key. Unlock the
driver's door using the key and then switch the ignition switch to the on position. If that doesn't
work exit the vehicle and roll up all windows, then use the key to lock the driver's door. Wait
for fifteen minutes and unlock the drivers door using the key, start the engine within 15
seconds of opening the door.
To see alarm system questions and answers please visit our forum. If you need free car repair
advice please ask our community of mechanics we are happy to help.