The Honda Fit is a top-ranked subcompact car known for its practicality.
As with any vehicle, the Fit’s alarm may go off for seemingly unknown reasons.
If your Fit alarm keeps going off, this article is here to help.
Table of Contents
Why Does My Honda Fit Alarm Keep Going Off?
A Honda Fit alarm is usually triggered by a faulty hood switch or door switch. Other common causes include key fob issues, battery issues, rust and corrosion on door hinges and various electrical issues.
1. Faulty Hood Switch
A faulty hood switch is a very common cause of unwanted alarms on the Honda Fit.
The switch is typically integrated into the hood latch.
The small electronic device is designed to detect whether the hood is open or shut and is an important part of the car’s alarm system – if it is broken, loose or dirty it can send false readings to the car’s computer thus triggering the alarm.
- Pop the hood and locate the hood switch.
- Check for any obvious damage, rust or loose connections.
- Give the hood switch a clean too (use contact cleaner), as dirt and grime can cause issues.
- You can test the switch with a continuity tester.
If you are mechanically inclined, you can buy a new hood switch online and replace it yourself. Otherwise, we’d advise visiting your local mechanic.
Owners on FitFreak.net had this to say about the matter:
“It is almost certainly the front hood latch sensor… You can replace the whole latch assembly in about an hour with ease. Or, I believe you can simply disconnect the sensor on that latch which is actually quite difficult to do. Easier to just swap the part. Ours was intermittently doing this for two years, and each time I thought I fixed it, it eventually came back. Nothing for more than a year since I replaced the latch.”
“My alarm kept going off last winter. After some googling I found that Honda hood latch sensors have a tendency to fail. I removed the sensor, packed the connector with silicone grease and wrapped it in electrical tape. The sensor sees the hood as ‘closed’ when the circuit is open so unplugging the sensor permanently opens the circuit. No issues since.”
Over at the HondaFit subreddit, here is what a couple of owners mentioned:
“My 2008 Honda fit was doing the same thing when I bought it. It turned out to be the Hood Latch Sensor, and the cheap fix was to unplug it.
What happens is the sensor can get rust on the plug and doesn’t make a solid electrical connection. For this reason it will trigger the alarm to go off because it thinks someone is breaking open your hood…”
“ … People have complained that the hood latch switch can malfunction sometimes and cause the alarm to go off.”
2. Faulty Door Switches
Faulty door switches (including the rear hatch) are another common cause of random alarms on the Fit, similar to the hood switch, these switches monitor the open/closed status of the door – if damaged, faulty or dirty they can send false readings thereby triggering the alarm.
Door switches are a common point of failure as they are subject to wear and tear due to the doors being continually opened/closed/slammed etc.
The door latches and door switches can get dirty too which can cause issues, so the first thing you should do is give all door latches a good clean and spray some WD-40 on the latch and work it in to see if that helps.
Also check the wiring leading from the body into the door for any signs of damage, it should be in a flexible hose on the hinge side of the door.
If you suspect the alarm issues are linked to the door switch, ask your dealer to run a diagnostic test to try and pinpoint the fault.
One owner shared an issue with his rear hatch (trunk) switch on FitFreak.net:
“Some electrical connectors on the trunk locking mechanism broke sending a signal to the trunk light that it was open, preventing me from locking the door…”
One owner on the HondaFit subreddit had this to say:
“I went and checked, everything was fine, locked it back up and went back into the restaurant I was at, only to have the same cop call me back 10 minutes later. I checked everything again, was super embarrassed but then I checked the trunk and my trunk latch had gotten stuck, so the trunk wasn’t ‘closing’ in the car’s computer, and was triggering the alarm. I found out this can be an issue in older fits, especially when the temps get lower.”
Related: Honda Fit Beeping Problems? (7 Causes & Solutions)
3. Accidentally Triggering the Panic Alarm on the Key Fob
If you keep your car’s key fob with other keys or objects in your pocket, then it is also likely that you are accidentally triggering your Fit’s alarm system.
To avoid this, have a dedicated pocket for your car key and make sure that it has enough wiggle room so that the buttons do not get accidentally pressed.
This was shared by one owner on FitFreak.net:
“I keep my Fit key on a keychain that has an ass-ton of other keys on it, and sometimes I’ll bend down to grab something and my Fit key will press up against another key in my pocket and set off the panic alarm, or lock/unlock my doors.”
4. Key Fob Running on Low Battery
A common cause of mysterious alarms on the Fit is a low key fob battery. Similarly, if the fob is dirty or dusty this can also cause alarm issues.
Give the inside of your fob a clean and replace the battery to eliminate this possible cause. It’s worth spending a bit extra for a good brand of battery.
- To open your key fob, stick your prying tool into the slit or gap between the two halves of the outer casing and gently apply upward pressure to pop open the device.
- Remove the battery.
- Give the key fob a good clean to remove any dirt or fluff – a cotton swab and some rubbing alcohol should do the trick.
- Check for damage, rust or loose connection (you may need a new key fob depending on what you find).
- Be sure to insert the new battery facing the right way up.
- Assemble the outer casing of your key fob by clamping them back together.
On FitFreak.net, one owner had this to share:
“ … I then replaced the FOB battery in both FOBs and boom, the alarm hasn’t gone off in 5 days. It was going off last Wednesday every time I locked it! So try replacing the FOB battery!”
We found one owner post this on the Honda subreddit:
“ … I remember in my old 98 Honda the alarm wouldn’t stop going off non stop and it turned out the damn remote battery needed to be replaced.”
5. Faulty Key Fob
Another reported cause of nuisance alarms on the Fit is a faulty key fob.
If you have 2 remotes, try taking the battery out of one and use the other for a while.
If the alarm problems persist, and you have tried cleaning the inside of the fob(s) and changing the battery, the best thing to do is speak with your dealer.
One owner on FitFreak.net suggested the following:
“Have you swapped keys yet? Could it be that your key has gone bad and it needs to be replaced?”
6. Drained 12V Battery
A faulty or weakened car battery causes a variety of problems, including accidentally triggering the Fit alarm.
The best thing to do is take your Fit for a battery health check, these are usually quite inexpensive or sometimes free such as at AutoZone.
Or you can test it yourself with a multimeter (see the guide at the end of this article).
A healthy 12V battery should be about 12.6 to 12.8 volts while a weakened battery reads below 12 volts.
A couple of owners on the MechanicAdvice subreddit shared this:
“When I leave the headlights on for 2 mins before taking a reading it reads around 11.5v. Then when starting it dips below 10v. So perhaps this is actually a battery issue.”
“Dead battery and/or not enough ground. Check the cables that connect the battery. Could be corroded inside the cable. Had that happen to one of my cars. Had to cut it back and clean up what I could and re-terminate it. Ima say dead battery still though. Fresh battery will read somewhere in the 14.6v area, 12.6 would be under load (car starting).”
7. Loose or Bad 12V Battery Connections
Loose or bad 12V battery connections can cause a number of problems, including triggering the alarm of your Fit.
A bad connection can be caused by dirt or gunk buildup.
The terminals may have come loose from driving and vibrations etc.
Make sure the engine is off before doing any work on the battery.
- Inspect the battery and look for any signs of damage, dirt build-up, rust, or corrosion.
- Disconnect the battery and loosen the nuts on the clamps using a wrench.
- Remove the negative clamp, marked with a “-” first.
- Clean the terminals with a toothbrush dipped in a mix of baking soda and water, rinse with distilled water and dry with a cloth.
- Reconnect the battery, ensuring tight connections.
Related: 9 Common Honda Fit Locking Problems (Solved & Explained)
8. Rust and Corrosion on Door and Hood Latches
Rust and corrosion can also damage the latches and switches, which may trick the sensors into detecting that a door or the hood is open.
If your car is frequently exposed to salt (road salt or coastal air salt) or wet/snowy conditions, then your Fit is at greater risk of corrosion.
A simple yet effective solution is to lubricate your car’s hinges just to provide a layer of protection against rust-causing agents.
One owner on FitFreak.net shared this:
“ … If you live in an area with snow, and things are prone to rust, I would suggest lubricating things like door hinges, latches, etc. I also need to replace the door hatch handle, since it is rusted as well. so good luck to all.”
9. Incorrectly Installed Aftermarket Alarm
An incorrectly installed or faulty aftermarket alarm system is a common cause of nuisance alarms.
Aftermarket alarms are typically far more complex than any factory-installed equipment which makes them more prone to issues.
They may also have been installed by incompetent individuals.
If you are experiencing issues with an aftermarket alarm, the best thing to do is speak with a reputable auto electrician.
10. Damaged Wiring
Damaged electrical wiring can cause a wide range of problems, it can often be tricky to pinpoint too and you may need to have an auto electrician run some diagnostic tests.
11. Animals Climbing On The Vehicle
If your alarm has been set off in the middle of the night, it may have been by an animal climbing on the car.
Have a look for footprints on the hood and the roof.
12. Not Closing Doors, Hood, or Trunk Properly
Sometimes a false alarm can be caused simply by not shutting a door properly, including the hood and trunk.
13. Faulty Body Control Module (BCM)
A faulty body control module can cause a wide range of issues including nuisance alarms.
- The BCM is in charge of electrical communication from different electronic systems.
- This includes the car alarm system, lock-unlock functions, climate control etc.
If you feel that your BCM is the culprit behind random alarm activation, then book an appointment with your local dealership to have it inspected.
Alternative Suggestions
Check for Recalls or TSBs
By entering your car’s VIN number on Honda’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.
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.
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 Honda Dealership
If needed, take your Honda 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 your unit is still under warranty then they should fix and resolve the issue for free.
How to 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.
Related: Honda S2000 Alarm Going Off? (13 Causes & Solutions)
Sources
https://owners.honda.com/vehicle-information/information/2020/Fit/manuals
https://owners.honda.com/service-maintenance/recalls
