The Chevrolet Cobalt is a sporty-looking compact car.
Like any car, its not immune to problems, and car alarm issues can arise.
If your Cobalt’s alarm keeps going off, read on…
Table of Contents
Why Does My Chevrolet Cobalt Alarm Keep Going Off?
A Chevrolet Cobalt alarm is usually triggered by a faulty hood switch or door switch as these sensors are prone to defects or damage after several years of use. Other common causes include key fob issues, a faulty BCM and 12V battery problems.
1. Faulty Hood Switch
A faulty hood switch is a common cause of unwanted alarms for Chevrolet vehicles, including the Cobalt.
The switch is typically embedded in 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 well-versed mechanically, you can buy a new hood switch online and replace it yourself. Otherwise, we’d advise visiting your local mechanic.
“Your hood latch switch has failed or your hood isn’t closed properly…” – YourCobalt.com
“I had an issue where my hood latch sensor was corroded and it caused the alarm to go off randomly, as well as the car to “kill” when trying to use the remote starter because the car thought the hood was open. New hood latch sensor fixed it…” – YourCobalt.com
2. Faulty Door Switches
Faulty door switches are another common cause of random alarms on the Cobalt, 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.
3. Loose or Bad 12V Battery Connections
Loose or bad 12V battery connections can cause a number of problems, including triggering the alarm of your Cobalt.
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 – symbol 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.
“Make sure your battery connections are clean. Take the cables off the battery and clean them well. Also trace the ground to see where it goes and see if it is tight. If a battery tester or load tester is available, test that battery while you are at it…” – FixYa.com
4. Drained 12V Battery
A faulty or weakened car battery causes a variety of problems, including accidentally triggering the Cobalt alarm.
The best thing to do is take your Cobalt 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.
5. Accidentally Triggering the Key Fob’s Panic Button
It is not uncommon for owners to unintentionally activate the panic alarm of the vehicle.
While a lot of owners have chalked it up to poor key fob design, a few others have attributed unintentional triggering to other objects in the same pocket as the key fob.
An easy fix for this is to have a dedicated pocket for your key fob, free from any other objects (such as pens or house keys).
“ … Examine your keyring. I had a keychain that was pressing the panic button while the keys were in my pocket.” – CobaltSS.net
Related: 6 Best & Worst Chevrolet Cobalt Years (Facts & Stats)
6. Faulty Key Fob
Another reported cause of nuisance alarms on the Cobalt 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.
Here is a quick workaround provided by an owner on ChevroletForum.com:
“I haven’t used the remote in a couple of years (replaced batteries but still wouldn’t work) and the electronic locks on both doors wouldn’t work so I’ve been manually locking/unlocking with no problem…”
7. Key Fob Running on Low Battery
A common cause of mysterious alarms on the Cobalt 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.
8. Unlocking Vehicle Manually
If you lock your vehicle using your key fob and unlock it manually (using the car key), then your alarm will trigger.
As part of the security protocols of the car, unlocking and locking must be done using the same process.
Therefore, if you lock your vehicle manually, you must unlock it manually. If you lock your vehicle using your key fob, you must unlock it using your key fob as well.
“If you lock the door with a key fob you have to open it with a key fob or the alarm goes off.” – YourCobalt.com
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. Faulty Body Control Module
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.
Replacing or repairing a BCM is quite technically advanced and we suggest leaving this to the experts.
“I would start by re-seating all the connectors several times on BCM to clean any corrosion since this seems to be the origin of your problems. Disconnect the battery first. Remote start won’t work if you have check engine light!” – YourCobalt.com
11. Water Damage
Water leaking into the vehicle’s electrics and latches can cause issues.
You will need to visually inspect your van and look for any signs of water ingress.
Around the door seals are a good place to start.
12. 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 front hood is open.
If your car is frequently exposed to moisture or other external elements, then you should routinely inspect critical areas of your vehicle for any sign of rust or corrosion.
One owner mentioned a TSB regarding this on ChevroletForum.com:
“ … There is a tsb for that. The door lock switches are corroded and sticking.”
13. 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.
In some instances, rodents may have chewed through an electrical wire.
14. 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.
States such as Illinois, Indiana, Iowa, Texas, Wisconsin, and Carolina have large wild raccoon populations.
Have a look for footprints on the hood and the roof.
If you have a CCTV system, examine the footage. These animals usually appear during the night.
15. Not Closing Doors, Hood, or Trunk Properly
Something as simple as not properly closing the doors, hood, or trunk will inevitably trigger the alarm.
Make sure to check if you have closed every point of entry of your vehicle to avoid accidentally tripping your Cobalt’s alarm.
Alternative Suggestions
Check for Recalls or TSBs
By entering your car’s VIN number on Chevrolet’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.
“Just an idea, try disconnecting the battery!” – CobaltSS.net
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 Chevrolet Dealership
If needed, take your Chevrolet 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.
Sources
https://www.chevrolet.com/support/vehicle/manuals-guides
https://www.chevrolet.com/ownercenter/recalls
