The Santa Fe is one of Hyundai’s most popular choices.
Like any other car, it’s not uncommon for the alarm to go off at random.
If you’re Santa Fe alarm keeps going off, this article will cover the most common reasons why.
Table of Contents
Why Does My Hyundai Santa Fe Alarm Keep Going Off?
A very common cause of an alarm going off on a Hyundai Santa Fe is the rear occupant alert being triggered by a pet dog, wind, or a bug. Other common causes include a faulty hood latch sensor, a bad electrical ground, key fob issues, 12V battery issues or a faulty BCM.
1. Rear Occupant Alert
The most common reason why a Hyundai Santa Fe alarm goes off at random is due to the rear occupant alert being triggered. This can be triggered by a bug in the car, a dog being left in the car or even wind blowing in the car if the windows or sunroof is left open.
This technology was first showcased in 2017, so if your model is older than that then this is not the cause of the alarm.
The system is designed to prevent children from being accidentally forgotten in the car (risk of heatstroke) or accidentally being locked in the car.
- Ultrasonic sensor detects movement in the rear seats
- Horn sounds, lights flash and a Blue Link alert message is sent to the driver’s smartphone if movement is detected
- If you lock the car with the windows or sunroof open a gust of breeze can trigger the sensors and set the alarm off.
- A trapped fly or bug is enough to trigger the sensors.
- If you have left your dog in the car this will also cause the rear occupant alert to be triggered.
You can simply turn off the rear occupant alert to prevent this from happening.
Here is what the manual says:
Make sure that all the windows are closed. If the window is open, the alert may operate by the sensor detecting an unintended movement (e.g. wind or bugs)
Here is what Santa Fe owners had to say on hyundai-forums.com
“Could it be the rear occupant alert.. I know sometimes on mine shadows get detected as people. It’s so annoying. Everytime I turn off the car and open the door if I see the alert for rear alert system I just got into a habit of pressing ok to disable the alert until the next time the car is started.”
“I’m not sure about shadows but if one of the rear windows is down slightly it will activate the rear occupancy alert. Maybe hop in the car and check the windows.”
“You can deactivate ROA in the User Settings of the LCD Cluster Display. I would only do this until you get a chance to have your dealer check it out.”
“Did you leave your sunroof open? I had my ROA get triggered because I left my sunroof open while making a quick run into the store. As mentioned above, you can try using Bluelink to unlock the doors with your neighbor around, have them open the rear doors so that the ROA gets disabled, and lock the doors again. I do wonder how long it has been since you have been getting alerts, b/c the ROA sensor is only supposed to monitor for 24 hours.”
How to Disable Rear Occupant Alert
You can disable the rear occupant alert on the display screen.
- Select “Setup”
- Select “Vehicle”
- Select “Convenience”
- Untick “Rear Occupant Alert”
2. Faulty Hood Switch
Another common reason why a Santa Fe alarm will go off mysteriously is due to a failed or faulty hood switch.
Also known as a hood latch sensor, this electrical component reports the state of the hood.
When the alarm is armed, the hood should be shut and the switch will confirm this to the car’s computer.
If the hood latch sensor is damaged or broken then this can cause the alarm to go off at random, as it will report an open hood when in actual fact it is closed.
You may also see a warning on the dash such as “Hood Open”.
Hood latch sensors often get dirty and clogged up with grime so it’s worth giving it a thorough clean and some lubrication first.
If you’re a hands-on type of person, you can replace this sensor quite easily with the help of a YouTube tutorial.
If not, have your local mechanic take a look for you.
One Santa Fe owner on HyundaiForum.com had this to say:
Generally it’s the hood switch because
– the hood either not fully closed
– the switch on the body got bent down while someone was working on the car
– the rubber bumper on the hood that touches the switch is missing
Owners on Hyundai-Forums.com gave the following advice:
“Beware the hood sensor and tailgate sensor – both are likely suspects.”
“Happy to report that, after disconnecting the hood switch 5 weeks ago, the alarm has not gone off again. Faulty hood switch seems to have been the problem.”
“Most likely it is the hood switch. On my Santa Fe, the alarm would go on and off after setting it. I noticed that it would go off when a vibration was encountered like a truck driving down the road. It seems that the vibration in the earth would vibrate the vehicle just a bit to make the hood pin not make enough contact. I therefore looked at the hood pin and noticed that the pin itself would make an indentation on the rubber bump on the hood. This made the pin not press down enough to make contact and thus made it go off.”
3. Key Fob Dirty, Damaged or Low Battery
A common reason why a Santa Fe alarm goes off at random is due to a faulty key fob or a key fob with a low battery.
The first thing to try is changing the fob battery, avoid using cheap batteries and make sure the battery is inserted the right way up.
When you have the fob open you should also give the inside a good clean with a cotton swap and rubbing alcohol.
Dirt and dust can accumulate causing issues with the electrical contacts.
If this hasn’t worked, try using a spare key fob but make sure that the other key fob is well out of range.
You should also ensure the spare fob is clean and has a fresh battery.
4. Low or Faulty 12V Battery
A low of faulty 12V battery can cause a wide range issues, including triggering the alarm at random times.
To rule this out, simply have a battery health test – this can be done by your local dealer, mechanic or even free of charge at an AutoZone.
You can also do this yourself with a multimeter, we’ve included a simple guide at the bottom of this article.
The battery should not have less than 12V.
It is also highly recommended that you give the battery terminals a good clean using a toothbrush dipped in a baking soda and water mixture and ensure the terminals are tight and free from gunk, debris, corrosion and dirt.
Similarly, if your Santa Fe has rusted battery terminals this can cause alarm issues as it will be unable to deliver the correct electrical power to various parts of the vehicle.
5. Bad Electrical Ground Connection
Electrical ground issues can cause a wide range of problems, and for some Santa Fe owners it has resulted in the alarm going off at random.
The ground cable can be traced to somewhere on the car’s chassis, for example the inner fender wall.
Its important that the ground is connected to a point that is free of dirt, rust or plating – all of which can act as an insulator and prevent a good ground connection.
Santa Fe owners at Hyundai-Forums.com had this to say:
“I had the same problem on my 2007 3.3L. The alarm would go off during the night also the outdoor ambient temp would not display. Traced problem to bad ground from negative battery cable to inner fender well. I removed paint and cleaned up the screws and haven’t had a problem. Also my outdoor ambient temperature display now works. Alarm problem was always worse after a rainstorm.”
“The negative battery cable connects to a rectangular aluminum block which bolts to a painted fender well thru 2 small screws. If I remember right I had to remove the fuse box and sand/scrape the paint, clean the screws and apply No-Ox to mating surfaces.”
6. Faulty Door Lock Sensors & Sticking Latches
A faulty door latch sensor is a common cause of Santa Fe alarms going off. Due to wear and tear and continually opening and closing the door, these sensors can wear out.
Similar to the hood latch sensor, your Santa Fe alarm monitors the doors to make sure no one is opening them.
Give all door latches a clean and some lubrication with WD-40.
A latch that is sticking can also trigger the alarm.
You will be able to ask your dealer to run a diagnostic test to show the last several reasons why the alarm was triggered.
This can help pinpoint the exact cause, especially if the reports show it was coming from one sensor in one of the doors.
7. Faulty Body Control Module
A Santa Fe alarm can be triggered by a faulty or damaged body control module.
The body control module or ‘body computer’ is the electronic control unit responsible for monitoring and controlling various systems associated with the vehicle’s body such as the alarm, immobilizers, power windows etc.
The body control module can develop corrosion on the pins or connections can become loose.
Other common symptoms of a bad BCM include:
- Repeated battery drain
- Starting problems
- Erratic electrical functions e.g. horn, wipers, lights, lights on the dash
- Security and alarm system problems
If you have the Bluelink app you can check this for clues as to why your alarm is going off.
It is best to check the app when the alarm is going off.
Disconnect the Battery
Sometimes mysterious alarm problems can disappear with a simple reboot, there are no guarantees here but it’s worth a try.
Disconnect the battery for 20 seconds and this resets many of the electronics in the vehicle.
Make Sure All Doors Are Shut Properly
This is sometimes overlooked, but make sure all doors, trunk and hood are shut properly.
Check For Warning Messages
When the alarm occurs can you see any lights or warning messages on the instrument panel?
This can give a clue as to what’s causing the alarm e.g. ‘Hood Ajar’.
Take it to a Hyundai Dealership
If needed, take your Santa Fe to the dealership.
Tell them you are NOT paying for a check on what the problem might be.
Ask them if they will check it for free.
Most dealerships and other places do quick/initial diagnosis for no money as they plan to make money for the repair of your vehicle.
If you’re car is still under warranty then they should fix and resolve the issue for free.
Check for Recalls or TSBs:
By entering your car’s VIN number on Hyundai’s recall page or the NTHSA’s Safety Issues & Recalls page you can determine whether or not there is a TSB or recall for your vehicle and if there is you’ll want to get it addressed.
A recall is issued by a vehicle manufacturer for issues that are safety-related, while a TSB covers components that may be malfunctioning but don’t compromise the safety of the vehicle.
Pull the Horn Fuse
Is your horn the alarm on your security system?
If so, pull the horn fuse.
That should keep it from going off all hours of the day and night.
Test the 12V Battery
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 car 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.
- The meter should display a reading, if the battery is fully charged the voltage should be between 12.2 and 12.6 volts.
- Anything under 12V and the battery should be charged or replaced.