The Toyota Prius is the first mass-produced hybrid vehicle.
It comes loaded with tech goodies and safety features that can often cause beeps, chimes and noises.
If your Prius keeps beeping and you’re unsure why, this article is here to help.
Toyota Prius Beeping While Off
If your Prius is Beeping while turned off it may be caused by low voltage from the 12V battery. You can also try disconnecting the 12V battery for 15 minutes and then reconnect it, this will recalibrate some of the car’s electronics. Alternatively, the battery in your Prius smart key may be running low.
If you are hearing a beep come from under the hood and it occurs approximately every 30 seconds, and it is accompanied by a flashing symbol or a big red exclamation point on the dash for a second, this indicates you may need to replace your 12V starting battery.
You can always check with a voltmeter, by measuring the voltage across the battery’s terminals.
If it’s under 11V then this is causing the beeps and you’ll need to replace it.
Smart Key Battery
Make sure your smart key battery isn’t running low, if it is you’ll hear an alarm inside of one beep.
- Check by pressing any button on the fob (you do not have to be near the car).
- If the red LED in the corner does *not* flash, then the fob battery is low.
Try changing the battery to see if the noise stops.
Toyota Prius Beeping
The most common causes of beeping on a Toyota Prius include the dash camera, spare set of keys left in the car, sunroof is open, faulty seatbelt sensors, loose electrical connections, navigation alerts, low tire pressure, defective door latches or one of the driver assistance features.
Beeping can be caused by a wide range of things, we’ve detailed the most common ones below.
Check the Doors and Hatch Are Shut
This may seem obvious, but before you try anything else, make sure you give the doors and rear hatch a good firm shut and ensure they are properly secured.
Spare Keys Left in Vehicle
If you’ve left a spare set of keys in your Prius you may hear a warning beep when you go to lock the vehicle as it thinks you are trying to lock the keys in the car.
If you have the Toyota factory installed dashcam you’ll likely hear this beep on startup.
You won’t see any warning lights come up on the dash, however, if you look behind your rearview mirror where the dashcam is located, you will see the dash camera flashing.
If you see an error flash, you may notice the micro SD card has not been fully inserted into the camera.
By pressing the SD card into the dashcam, this should stop the beeping.
However, if the SD card is in and it’s still beeping, press and hold the ‘action’ button while you turn on the car.
- Make sure the vehicle is completely off
- Make sure you are parked on level ground
- Make sure the camera has shut off
- Press and hold the action button
- Then start your vehicle
By doing so you will recalibrate your vehicle.
You should hear a couple of beeps and see a green light and you’re good to go.
Bluetooth Dropping Out
When your phone (or accessory) loses its Bluetooth signal connection you may hear a beep.
Loose Connection: Seat Belt Sensors
Loose wiring or a bad electrical connection may be triggering a beeping noise.
It’s worth checking underneath every seat in the vehicle and checking / pressing together all the plastic wire connectors to ensure they are all tight.
It’s also a good idea to do the same behind the glovebox.
Seatbelt Alarm & Weight on Seat
There might be a faulty sensor that isn’t recognizing that your seatbelt is fastened.
Alternatively, you may have some weight on the passenger seat like a bag of groceries or your pet dog which is triggering an alarm.
In which case you can try fastening the passenger seatbelt.
The Blind Spot Monitor warns the driver if someone is in their blind spot or if someone is coming up behind your vehicle when you start to reverse, a warning light will flash in your mirror and it should also make a beeping sound.
A faulty headlight switch or a faulty ignition switch may be the cause of the beeping.
Since the headlights being on, or the key being in the ignition will cause the chime to sound, one of these switches may have a loose connection or be faulty.
Check to make sure that none of your lights have burnt out, you should check your rear lights and brake lights too.
Burnt Out Airbag Warning Light
On many vehicles, if the airbag warning lamp has blown on the gauge cluster, the car will beep to warn the driver.
You should be able to see the light come on when you start the car.
Watch the Dash Display
This could give you a clue about what’s causing the beeping.
Does a specific warning light come on when you hear the beeps?
Also, keep an eye on the radio / infotainment screen, this might give a clue too.
Toyota Prius Beeping While Driving
If you are experiencing beeping whilst driving your Toyota Prius, this may be caused by a faulty door latch, if you have a ‘door ajar’ light on the dashboard then this is almost certainly the case, these latches can often become stuck.
Faulty latches are very common across all vehicles – you may need to have a latch replaced although you should first try lubricating it with something like WD-40.
If it’s not related to the door sensor/latch then it could be caused by a damaged wire.
A lot of mysterious beeps and electrical issues can be traced back to damaged wires or loose electrical connections.
No Beep When Locking Prius
This can be caused by a faulty door actuator or a faulty door latch; the car is unable to lock all the doors and is therefore not beeping.
If you can’t make your Prius beep when you lock it:
- Try to lock the doors using the key fob
- Place your key fob away from your car.
- Now go and check all your doors.
- You will find one of them will be unlocked.
- If there is not one unlocked, it maybe half way inbetween.
- Now open your car and inside lock all the doors.
- Check to see they are all locked.
- Now using the door lock inside, unlock them, you will find that one of them will not open.
- That’s the one.
Related: 17 Best & Worst Toyota Prius Years (With Facts & Stats)
Prius Beeps When Opening Door
If you are hearing a beep or chime when you turn off your Prius this is likely because you opened the door first without turning off the engine. It may also be caused by if you left the sunroof open.
- Engine running
- Put vehicle into Park.
- Turn off the Engine
- Open the door.
- Engine running
- Put vehicle into Park
- Open the door
- Turn off the Engine
It may be possible to disable this using the Toyota Techstream software.
Other Common Beeping Causes
- Door / rear hatch open or not closed properly
- Traction control (beeps when it activates)
- Exceeding speeds set in cruise control
- Door is open and key is ignition
- Seatbelt not fastened
- Headlights on / key in ignition when door is open
- Low fluids e.g. windshield waher fluid, engine oil etc.
- Reversing (in some cases)
- Spare set of keys locked in car
- A warning / error condition on the instruments
- Low fuel
- RSA (road sign assist)
- Lane Sway Warning (excessive swaying within the lane markings)
- Lane Departure Alert
- BSM (blind spot monitor)
- ICS (Intelligent Clearance Sonar)
- Park Assist
- PCS (Pre-Collison System)
- Red light camera warning beep
- Cell phone left under a seat
- Aftermarket head units
- Car battery needs replacing
Diagnosing Beeps With a Scanner
Another possible option if you’re hearing a beeping sound is to use an OBD2 diagnostic scanner tool.
These are fairly easy to use, you simply plug them into your car – there’s usually an OBD2 port under the steering wheel.
Once you have the scan codes you can research these online specifically for the Prius.
There are also OBD apps available so you can connect your car straight to your smartphone (either with a cable or Bluetooth) without even needing a scanner.
Related: Toyota Prius Alarm Going Off? (13 Causes & Solutions)