If you’ve ever turned the key in your Toyota only to see the dreaded “Smart Key and Start System Malfunction” warning message suddenly appear on your dashboard, you know how unsettling that can be. Especially if your car refuses to start altogether.

As an auto technician, I’ve helped many owners troubleshoot and resolve this issue. In this blog post, I’ll explain exactly what that warning means, what causes it, and how to start your Toyota again.

Whether the fault lies with your smart key fob batteries, a failed electronic control unit, or even signal interference, I’ve got you covered for pinpointing and correcting the cause. I’ll also provide some handy tips to help prevent smart key and smart entry problems from cropping up in the first place.

By the end, you’ll understand why the “Smart Entry and Start System Malfunction” message appeared, how to make it go away for good, and how to avoid future issues with your Toyota’s push-button start system. So let’s get started!



Seeing the ominous “Smart Entry and Start System Malfunction” warning flash on your Toyota’s dashboard is unsettling. It means a key component of your car’s push-button start system is malfunctioning. Specifically, the smart key fob, wireless transmitter, or electronic control unit has failed or lost communication.

This prevents your car from recognizing your key fob when you try to start it. You’ll generally be unable to start the engine while this warning persists. Other smart key features like keyless entry and push-button start will fail until the root cause is addressed. This malfunction prevents your Toyota from verifying your key, necessitating a trip to the dealer or repair shop.


There are a few potential culprits behind the dreaded “Smart Entry and Start System Malfunction” message popping up on your Toyota’s dashboard.

Dead Car Battery

The most common trigger for this error message is a dead car battery. If electronics were left on overnight, the battery drained is old and can no longer hold a charge, or if an electrical glitch is slowly sapping the battery, you may be left with insufficient power to start the car or run the smart key system. This is especially common after parking your car for a few days during cold weather.

Smart Key Fob Battery Died

On rarer occasions, the issue is with the smart key fob itself. If the battery in your key fob dies, the car cannot recognize the key, producing a malfunction message. Or, in some cases, an outright computer system failure can lead to a communication breakdown between the key and the car.

How to Fix the Smart Key Malfunction

Now that we’ve explored what’s causing your Toyota’s smart entry system issues let’s talk about solutions for getting back up and running.


Previously, it was noted that many individuals encountered this problem due to a dead car battery. To resolve this issue, you will have to jump-start your vehicle.


Jump-Start Your Vehicle If your Toyota fails to start and shows the smart key malfunction message, first try jump-starting the battery. Use jumper cables connected to another vehicle or a portable jump starter pack. Follow the proper procedure for your vehicle by securely connecting the positive and negative terminals. Let the vehicle charge for 5-10 minutes before attempting to start. If it powers on, drive around for 20-30 minutes to recharge the battery. If the message still displays, move to the next step.


Check Your Smart Key Fob Battery If jump-starting doesn’t work, use new batteries to replace the dead ones in your key fob. Toyota smart keys use a standard CR2032 coin battery. Flip the key fob and locate the slot to access the battery compartment. Snap the new battery into place with the positive side facing up and reassemble the key. Retry is starting your Toyota. If it still won’t start, continue to the dealership fix.

Contact Your Toyota Dealer

Schedule a service appointment with your Toyota dealer. Their certified Toyota technicians can diagnose the specific failed component causing the smart entry system malfunction. Common fixes include replacing the push-button start control module, installing updated key fob software, or reprogramming the system. Follow their expert repair recommendations to clear the warning message for good finally.


You can still start your Toyota even with a malfunction of a smart entry system. This provides a handy temporary fix while you address the underlying issue.

  • Unlock the car door using the metal key built into your key fob, hidden behind the logo
  • If your Toyota is less than 15 years old, hold the key fob logo flat up against the ENGINE START STOP button
  • The logo transmits the radio signal to start the car without a full smart key function
  • For Toyotas over 15 years old, press the smart key deactivation switch located below the steering column
  • This turns off the malfunctioning system so that you can start with just the key fob present

Follow this method to get back on the road quickly while you schedule repairs to restore complete smart key convenience.


While the “Smart Entry and Start System Malfunction” error can stem from various issues, there are precautions you can take to avoid seeing it again in your Toyota:

  • Keep jumper cables or a portable jump starter in your car if the battery dies.
  • Double-check that all lights and accessories are off before leaving your car parked overnight.
  • Replace the battery in your smart key fob periodically as a preventative measure.
  • Purchase extra CR2032 coin batteries for your key fob to have on hand.
  • Consider installing a battery tender to maintain optimal charge if you don’t drive regularly.
  • Stay up to date on all recommended maintenance for your car’s electrical system.


The smart key system error is inconvenient but manageable. Try jump-starting first. If that fails, deactivate the system to operate your vehicle while you schedule repairs. Battery issues cause most problems, so keep spare batteries and jumper cables in your car for self-rescue. Infrequent computer failures will still require the help of a qualified mechanic for diagnosis and repairs. The smart key is convenient when working but has vulnerabilities. Being prepared with supplies and contingency plans will enable you to minimize disruption if problems occur.