Toyota Avalon: 12 Common Problems (Solution Guide)

The Toyota Avalon is a slick, stylish, full-size sedan that was produced from 1994 to 2022.

Although it has excellent reliability, it has its share of problems.

In this short guide, we’ll help you get to the bottom of the most common issues.

Toyota Avalon Alarm Keeps Going Off 

The most common reason for a Toyota Avalon alarm going off randomly is due to a defective hood switch. Another common cause is that the 12V battery is about to die.  

If your Avalon car alarm keeps going off randomly without something obvious triggering it, the anti-theft system is not functioning as it should.

Detailed below are the most common reasons:

Faulty Hood Switch/Door Switch 

Hood and door switches are responsible for triggering the alarm in the event of someone trying to force their way into your vehicle.

When the vehicle is locked with the fob, the anti-theft system is armed.

Thus, if the door or the hood is opened or unlocked by force while the system is armed, it will trigger the alarm.

A faulty hood switch or door switch can cause the alarm to go off even when the door/hood is not being opened. 

It could also be the rubber cap has deteriorated far enough so as to not allow full depression of the switch.

It’s important to remember that the hood latch and door latches should be cleaned, lubricated (WD-40), and free of debris.

If the hood/doors are not closing properly, it could cause the switch to trigger the alarm. 

Note: This is a very common cause across numerous Toyota models.

12V Battery 

The first thing to check when dealing with this issue, is the anti-theft system’s power source, which is the 12V battery.

A battery that is on the brink of failure or running low on voltage can cause the alarm to go off.

This is because the anti-theft system triggers the alarm when power is interrupted while the system is armed. 

So, having the battery tested and replaced if necessary, is always the best place to start when dealing with this concern. 

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 problem.

If you’ve had the battery for more than 3 years it might be time for a new one.

Also, ensure your battery connections are tight and clean and free from corrosion.

Glass Breakage Sensor (GBS) ECU 

The Avalon security system comes equipped with a glass breakage sensor.  

This sensor can detect tapping or breakage of the glass, which then sounds the alarm. 

The sensor is controlled by an electronic control unit (ECU) which is located behind the glovebox. On the GBS ECU, there is an adjustment screw to control the sensitivity of the system. 

It is possible the sensitivity is set too high, causing the alarm to be triggered by occurrences such as thunderstorms or big gusts of wind. 

Always follow Toyota’s recommendation when setting the sensitivity.

Toyota Avalon Keeps Beeping

Many Avalon owners found their vehicle was beeping because the parking brake was slightly engaged, or they set something on the passenger’s seat (such as a bag of groceries). Other problems could be defective door switches or park assist sensors. 

The Toyota Avalon can beep at you for many different reasons – but when it is seemingly at random or unprompted, it can leave owners frustrated.

Parking Brake

If the parking brake is engaged while the vehicle is in motion, the Avalon will try to indicate the driver to release it by beeping.

Rightfully so, as driving with the parking brake engaged will wear out brake pads and make them less effective, it’s also not very safe. 

Weight on Passengers Seat

Another incident that can cause beeping, is objects placed on the passenger’s seat. 

The seat has weight sensors used to determine if the airbag should be deployed or not, and used to activate the passenger’s seatbelt indicator.  

If the seat weight sensors detects a load on the passenger’s seat but the seatbelt is disconnected, an audible chime will follow.

If you wish to place items on the passenger seat while driving without the beeping, simply connect the passenger seatbelt.

Also be sure to check all the doors and the rear hatch are closed properly. 

Faulty Door Switch

If all of these conditions are met, the problem could lie in a defective door switch, leading the Avalon electronic system to think a door is open while the vehicle is in motion. 

A park assist sensor could also be to blame.

Toyota’s park assist sensors are sensitive, and a small amount of dirt, moisture, or damage could cause them to chime continuously, though it will most likely display it on the Multi-Information Display (MID).

Spare Keys Left in Vehicle

If you’ve left a spare set of keys in your Avalon 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.

Toyota Avalon Keeps Cutting Out 

If your Toyota Avalon keeps cutting out, it is likely due to an electrical problem in the main battery/ignition circuit. This electrical problem could be caused by a loose or corroded ground cable, a faulty ignition relay, or poor contact between battery terminals and  posts. 

Avalon owners have reported that their car would suddenly lose all electrical and engine power abruptly. 

This can leave drivers without power steering,  power brakes, acceleration, exterior lights, driver assists, etc.

This issue can take extensive diagnosis, and finding the root cause can be tricky. Thus, repair costs will vary depending on how easily your mechanic can locate the source of the problem. 

However, according to our research, the main causes of this complaint were:

  • Loose/corroded battery terminals 
  • Loose/corroded electrical ground cable 
  • Loose electrical cable connected to fuse box 
  • Defective ignition relay 

Due to the technical nature of this concern, we recommend leaving your vehicle in the hands of a trained professional, specifically an auto-electrician.

Toyota Avalon Glove Box Keeps Opening 

When the glove box of your Avalon keeps popping open, it is usually caused by a broken latch. Unfortunately, latches cannot be replaced individually, so the entire glove box will need to be replaced. Before buying one though, ensure nothing is jammed in the way of the latch or the sides of the glove box. 

When this problem occurs, owners should check to ensure the box is not overloaded, and the mechanisms (such as the hinges or latch) are not jammed by an item.

But if this is not the case, then a latch may have gone bad. When the latch breaks they are no longer able to support the weight of the box and keep the glove compartment closed. 

The latches cannot be replaced individually, so the whole glove box will have to be interchanged. 

On a light note, this repair is relatively easy, which is why “DIYers” should have no issue attempting this repair so long as they have some basic hand tools.

The box itself can be pricey though, sometimes ranging into the hundreds of dollars.

For those on a tight budget a used one might be a better option. 

Toyota Avalon Headlights Keep Burning Out 

Headlight bulbs should not require frequent replacement. If you find the bulbs burn out all too often on your Avalon, check your alternator output,  or for moisture inside the headlight. It’s also important to wear gloves when installing bulbs, oil from fingers can decrease bulb life. 

A common cause of decreased headlight bulb longevity lies in the installer not wearing gloves. 

This is because the oil on your hands disrupts the uniform heating process.

But if you always wear gloves when changing bulbs, then it may be caused by moisture in the headlight assembly itself. 

Headlight assemblies should be sealed and free of any moisture. If not, this moisture can cause the bulb to fail prematurely. 

Lastly, the alternator output voltage should be checked.

If the voltage regulator in the charging system fails, excessive voltage can be sent to the headlights causing them to overheat and burn out. 

Toyota Avalon Clicking Noise, But Won’t Start 

Some Toyota Avalon owners experienced their vehicle making a clicking noise but not starting. This problem is largely caused by a weak battery.  Alternatively, a malfunctioning starter motor could be to blame. The starter solenoid is not the issue though, as it is the source of the clicking noise. 

A vehicle clicking and failing to start is a common problem that is by no means exclusive to the Avalon.

The majority of issues stem from a weak or defective battery.

A battery without enough power to start the vehicle will cause a no-start, yet solenoids or relays may still make a clicking noise. 

Always have the battery tested first, and confirm connections are clean and tight. Corrosion or poor connections can cause the battery to behave as if it is weak. 

Damaged battery cables could also be the root cause, and almost always exhibit the same symptoms as a failing battery. 

If the vehicle’s 12V battery passes a test, then the next likely cause is the starter motor. 

The starter motor is an electric motor that functions by electrical current from the 12V battery. The motor spins a gear to turn the engine over. It is engaged by a solenoid. 

When the motor wears out, it fails to turn the engine and get it started.  However, the solenoid still functions, which is the cause of the clicking noise. 

For the Toyota Avalon starter replacement, RepairPal estimates labor costs are between $62 and $78, while parts are priced between $219  and $418 on average. 

Toyota Avalon Windows Keeps Going Down

Some Avalon owners have noticed that their driver’s window goes down after they’ve turned off their vehicle and walked away, fortunately this is an easy fix and it is usually caused by slamming the door too hard.

  1. Open your door you will see a black plastic plug near the door handle.
  2. Pry it out with a small screwdriver shine a flashlight in the hole you will see a red plastic connecting link that should have a metal rod with a 90-degree bend sticking through it.
  3. Take the plug out of the passenger side door and compare the two.
  4. Now take a stiff wire and bend a hook on the end and carefully lift the rod back in place.
  5. You may have to push it back in the hole with a slender screwdriver while lifting it with the wire.
  6. Also leave the key in the lock and have someone turn it slowly to help line up.

If you feel comfortable removing the door panel, this might be easier although you’ll have to deal with a lot of clips.

You may also like: How Long Do Toyota Avalon Hybrids Last?

Toyota Avalon Won’t Lock 

Usually when the Avalon won’t lock, the cause of concern lies in a fob being left in the vehicle, or the doors not being closed all the way.  However, if this is not the case, it may be caused by a dead key fob battery, worn-out door lock actuator, or blown fuse.

Toyota implements Power Lock and Smart Entry systems in their new vehicles however they are not without their share of problems. 

Here’s a list of what to look out for when researching why your Avalon won’t lock: 

Fob In the Vehicle / Doors Not Closed 

If your Avalon has a push-button start, it uses proximity sensors to determine how close the fob is to the vehicle, and whether or not it is in the cabin. 

The Avalon comes off the lot with two key fobs – meaning one could be left inside the vehicle as you try to lock it with another. 

If a key fob is inside the vehicle, it simply will not lock, especially a smart key. 

If you cannot find the key fob anywhere but suspect there still might be one in the cabin of your Avalon, simply try to start it with no known keys inside the vehicle.

If it starts, there must be a key fob inside. 

Also ensure all doors (including rear hatch) are closed. If not, the door lock system will refuse to operate.

Key Fob Battery Dead 

Like many electronic gadgets, the key fob has a battery.

This battery is known as a CR2032 battery, it is widely available and only costs around $5. 

If the battery in the fob goes dead, it needs to be replaced.

A relatively easy task with minimal tools required, and some dealerships may even replace it for you, free of labor charges. 

Blown Door Lock Fuse 

Even though blown door lock fuses are uncommon, they are not unheard of. 

If the door lock fuse blows, it will prevent the entire door lock system from functioning. 

Fuses can be easily accessed and inspected by pulling them out of the fuse box. 

A blown fuse is usually caused by an electrical short though – this occurs due to exposed or damaged wires or connections.

So if you find a blown door lock fuse and replace it, it may continually blow until the wiring fault is rectified. 

Defective Door Lock Actuator

The door lock actuator is an electrical device responsible for moving the lock mechanism when a lock signal from the key fob is detected. 

A defective door lock actuator typically only causes one door lock to fail,  rather than all doors. 

This component requires testing, and checking for supply voltage and ground presence in the harness connected to the actuator. 

We recommend leaving a door lock actuator diagnosis and repair to a  professional automotive technician due to the technical nature of the problem.

Toyota Avalon Won’t Start When Hot 

If you find your Avalon won’t start when hot, more often than not it is caused by a bad starter. This is because as heat increases, the starter motor windings resistance increase. Some Avalon owners with this issue fit a 2.2KW starter instead of the 1.6KW starter. 

Assuming your vehicle’s battery has been tested and is fully charged (if it isn’t, start there) the problem lies in a weak starter motor.  

When starter motors get too hot, they tend to act up. This is because the copper windings inside the motor increase in resistance, making it harder to spin the engine. 

If you lack knowledge with car repair, always consult a  professional. 

Toyota Avalon Won’t Start When Cold 

If you find your Avalon won’t start when cold, this is often caused by a defective battery.

A battery has two different ratings, cranking amps and cold cranking amps.  

Cold-cranking amps are the battery’s ability to start and turn the engine over when it is cold.

It is easier to start an engine in a warm environment than in a cold one

So it may have enough cranking capacity to start the vehicle when it is warm, but when it’s cold, it just isn’t enough to turn the engine over anymore.

Battery cells degrade over time and most 12V car batteries will last around 3-4 years.

Avalon Won’t Connect To iPhone 

When your Avalon won’t connect to your iPhone, you need to confirm the Bluetooth setting are enabled first, both on the vehicle and on the phone. Also, the system can only hold a max of 5 phones. Delete a device if you have too many. Lastly, check for updates, and check your phone’s compatibility.

Phone connectivity is a common issue for Avalon owners, and iPhone users are no exception.

However, there are a number of quick checks you should perform before you rush it into the service department. 

In the Avalon settings, be sure that your Bluetooth settings are enabled.

The same goes for your phone’s Bluetooth settings.

It may seem obvious, but it is often overlooked. 

Understand that most Toyotas (including the Avalon) only allow a max of 5  phones registered.

If you already have 5, you’ll have to delete one if you want to pair a new one. 

It never hurts to reboot the system, and/or clear the cache.

Just be sure you don’t completely reset or reformat either your phone or the Avalon – you may lose all of your data in the process. 

Some devices simply are not compatible with Entune.

There’s a list of compatible devices on Toyota’s website.

Always make sure your iPhone is running the latest iOS software, this can often be the root cause of a number of iPhone related issues.

If all else fails, you may want to contact your local dealer and check for any software updates.

There may be one available for your vehicle, or they may be able to pinpoint why your phone is not connecting.

Toyota Avalon Bluetooth Keeps Disconnecting 

When Bluetooth keeps disconnecting from the Avalon, owners found the easiest fix was to delete their phone from the Avalon Bluetooth device list, and pair the device again. If this does not work, confirm your phone is compatible with your vehicle, and confirm your Avalon has the latest software update. 

If your phone continually disconnects from your Avalon, it’s always best to try a few simple things first before you hand over any money to a technician. 

Firstly, delete the device from your Avalon’s Bluetooth device list.

Delete the Avalon from your device’s Bluetooth list as well if needed. 

If possible, clear the cache or perform a soft reset as well.

Key the vehicle off and back on again, and perform the pairing process. This method fixed the majority of owner’s problems with Bluetooth disconnecting. 

Always check your phone for the latest software updates.

Additionally, check with your dealership to confirm your Avalon has the latest update.

Toyota is always updating the software on their vehicles to fix glitches and bugs. 

If this does not help, check to ensure your device is compatible. A list of compatible devices can be found on the Toyota website.

Sources

https://www.toyota.com/owners/resources/warranty-owners-manuals.avalon.2017

https://www.toyota.com/owners/resources/warranty-owners-manuals.avalon.2020