Do Teslas Have a Check Engine Light – Or Other Major Malfunction Warnings?

By Zac Ludicrous •  Updated: 09/26/22 •  12 min read

Electric cars run entirely on battery power and are equipped with smart devices that display all the information about the car, including alerts or warnings. 

The Tesla Model S and Model X have them mostly on the dashboard or instrument panel, while the Model 3 and Model Y have them all on the touchscreen.

So unlike ICE (internal combustion engine) cars, Teslas don’t have a check engine light because they don’t have an engine.

However, with so many icons in front of you in a Tesla, it’s understandable that they can be confusing. Before you go to the service center, I’ll help you get familiarized with Tesla’s warning symbols so you know what they mean and what to do.

What’s the “Check Engine Light” Equivalent in a Tesla?

On your Tesla’s dashboard or touchscreen, you’ll notice a lot of warning icons that light up and go away, which is your car’s way of running a few initial diagnostics and validating systems.

To better understand them, let’s categorize them:

Tesla Error Messages

Tesla owners can receive several error messages on their EV, which Tesla refers to as Troubleshooting Alerts.

Tesla Dashboard Warning Icons

You’ll also notice a few indicator lights or warning icons on your Tesla’s dashboard that indicate the status of your car.

Tesla’s & Regular Diagnostic Tools

Standard cars often have an OBD (on-board diagnostics) port where mechanics can connect a device to pull the vehicle’s information and diagnose problems. It is mandated by the law and largely related to pollution controls in ICE cars.

A conventional OBD port is not available on Teslas. Instead, you can use the console connector found at the vehicle’s back seat to plug in an OBD scanner using a Tesla OBD adapter.

Tesla’s & Diagnostic Apps

Like other smart devices and electric vehicles, Teslas can use applications to diagnose issues via software.

Common Tesla Error Messages and How to Fix Them

Being a smart car, Tesla has a long list of troubleshooting alerts that you may possibly get. But the good thing about this is that you know exactly what’s wrong with your vehicle and it tells you what to do. Either you can do something about it on your own or you need to contact a Tesla service center.

That’s way better than wondering what a specific blinking light means and not knowing what needs fixing.

Based on my research, here are the most common error messages that Tesla owners encounter.

1: (UI_a137) Active service connection to vehicle

Service performing remote diagnostics

To diagnose or repair an electric vehicle, a technician or service professional logs in to your car remotely. During the connection, you may notice some loss of infotainment capability, but you need not worry about it.

It’s still okay to drive your Tesla.

This specific error message should go away once the technician has finished diagnosing or repairing your Tesla. After that, you may have to reboot your touchscreen to restore full infotainment functionality.

Check out your car’s DIY guide on restarting the touchscreen for more information.

If 24 hours have passed and the warning is still showing up, use your Tesla mobile app to schedule a service.

2: (UMC_a002) Unable to charge – Mobile Connector GFCI tripped

Unplug charge handle from charge port and retry

Getting this alert means the ground-fault circuit interrupter (GFCI) in the Mobile Connector has tripped, preventing the car from charging.

This function, like the GFCI in a wall outlet, is meant to block the flow of electricity or interrupt charging when there is a problem to protect the charging equipment and, of course, your car.

There could also be other reasons behind this error message. It can be a problem with the onboard vehicle component, charge port, charging handle, or charging cable, but not your electric car itself.

Look for any moisture or pooled water in the charging handle and charging port.

If there’s too much moisture, wait until the inside of the charge port and the inside of the exposed area of the charging handle dry completely before trying to use it to charge again.

Inspect the charging equipment for any damage as well. If you notice any damage or deterioration on the cable, don’t use it anymore and try another charging equipment.

If it’s still okay to use, try charging your Tesla with it again. If the problem persists, consider using an alternative charging device.

Since this particular alert normally refers to the charging device and the external power source, it’s not an issue that can be fixed by scheduling a service. The recommended steps are to retry charging with the same or a different charging equipment.

If your charging devices aren’t working, head to a Destination Charger or Tesla Supercharger, which you can locate using the map on your car’s touchscreen.

You can also try other third-party charging stations so you can pinpoint the problem.

For further information on troubleshooting charging issues and the status lights of the Mobile Connector, refer to your owner’s manual.

3: (VCFRONT_a180) Electrical system power reduce

Vehicle may shut down unexpectedly

This means the electrical system can’t keep up with the voltage needed to support all your car’s functions.

Your EV may shut down abruptly if this warning is present while you’re traveling. It’s also possible that after your current drive, your vehicle will not restart.

You can reboot your Tesla Model 3 by doing a soft or hard reset.

Just like this Model X owner who got a bunch of error messages and fixed all of them by doing a hard reset:


If that doesn’t work, your vehicle likely doesn’t have enough electrical power to start driving if this notice appears while it’s in Park or when it first wakes up. That issue could be indicated by a second vehicle alarm.

Any unnecessary features should be removed or minimized to assist your car in maintaining sufficient electrical power for important functions.

If this alert continues to be active, contact Tesla to schedule a service right away. You may be unable to drive your car, and it may shut down or restart unexpectedly without service.

4: (VCFRONT_a478) Low voltage battery service is required

Schedule service – Vehicle may not restart

This specific error message means the low voltage battery is incapable of providing the necessary electrical support to drive or continue driving.

If this notice appears while driving, you must pull over safely as soon as possible.

Your Tesla would shut down all of a sudden or won’t restart.

You may notice some nonessential features are not available. This is expected and advisable so that your EV can preserve energy for essential functions besides driving until you can get it serviced.

This is one of the error messages that would require you to contact Tesla for servicing. If not, you may not be able to drive your car because it can shut down unexpectedly or not restart.

5: (DI_a201) Regenerative braking temporarily reduced

Regen will increase as vehicle is driven

If you get this alert, the performance of regenerative braking has been temporarily restricted to less than 65% of its maximum capacity. The dashed lines on the power meter represent the exact reduction.

The vehicle’s deceleration rate will be slowed, owing to regenerative braking, and more braking will be required to slow the vehicle (it’s the same as what gas-powered, non-electric cars need).

You’ll get this error message when:

Driving usually clears this notification since it lowers the battery charge level below 95% and warms the battery sufficiently.

This is an entirely typical part of how your car operates and shouldn’t cause concern. The message on the screen is just for your information.

You can find out more about regenerative braking from your owner’s manual.

If you’re doubting that any problem you have with your Tesla will be fixed, listen to this owner who shared his experience. He got a lot of error messages in his Model 3, and when he got his EV serviced, he was satisfied when he got his car back.

At 0:15, the owner detailed the error messages he got while driving and where it appeared.

Standard Warning Icons on a Tesla

There are plenty of icons and warnings that may show up on your dashboard or touchscreen. It’s your car’s way of doing some initial diagnostics and validating systems as normal. But it’s a different thing if one of these icons stays on.

You can see what the icons mean on Tesla’s Quick Guide for Owners, or you can check out our article on it.

There are seven icons on each side (left and right).

Let’s start with the ones on the left:

Left Icons

  1. Airbag
  2. Seat belt
  3. Front fog lights
  4. Rear fog lights
  5. Headlights
  6. Brights

Then these are the icons on the right:

Right Icons

  1. Traction control
  2. Air suspension
  3. Parking brake
  4. ABS fault
  5. Brake system fault
  6. Tire pressure
  7. Door, frunk, or trunk open

When you apply the brake to prepare for driving, these icons light up for a brief moment. In some cases, a message appears on the instrument panel or touchscreen. Contact Tesla if an indicator light fails to switch on or off.

Can You Run a Diagnostic on a Tesla? Do Regular Tools Work?

Tesla made diagnostic tools, service manuals, and other resources available for free in December 2020. They wanted to make room for the right-to-repair initiative, which allows owners to work on their electric vehicles themselves.

All this information was already available to everyone before, but owners had to be willing to get a subscription to access it.

But now Tesla vehicles can self-diagnose maintenance and repair problems and even order parts for fixes automatically.

The automation of some operations, such as live issue detection to instantly call a tow truck and loaner car, even before the vehicle comes to a stop, is part of Tesla’s series of measures to improve service.

According to Tesla CEO Elon Musk, the company aims to automate emergency service and repairs, but owners can cancel it immediately if they believe it is not needed.

If the problem can’t be resolved right away, Tesla’s remote diagnostics can often detect and pre-diagnose fixes so you can get service sooner when you visit a Tesla service center.

LOKI is a popular diagnostic software for electric vehicles. It detects defects, performs maintenance, and extends a vehicle’s present usefulness.

It also includes all necessary service functions for repairing and maintaining the Model S, Model X, and Model 3.

You can get a supplementary tool, such as a JTAG Cable LC005-SEC, for the Model 3 and Model Y that you connect to the MCU or media control unit of your car to modify the configuration hidden parameters using the LOKI Secured Configuration plugin.

You can also connect LOKI to the CAN bus of your Model 3 or Model Y with the LC006-C3 Cable CAN.

Want to see how it works? Watch the video below to know how to diagnose your Tesla using LOKI.

You can see the functions of LOKI and how to use it starting at 0:20.

Diagnosing Your Tesla with an App

There are also software-based diagnostic applications that you can download. 

The most common app is Scan My Tesla, which gives you real-time readings from the diagnostics port of the Tesla Model S, Model 3, Model X, and Model Y.

Note that this app needs an adapter cable and a Bluetooth OBD2 adapter to work.

One review said, “The software is comprehensive yet easy to use.”

Bjørn Nyland shows how the Scan My Tesla app works and how to install the adapter in the YouTube video below:

At 2:30, his phone is paired to the adapter via Bluetooth.

Another diagnostic app for Tesla is T-Diag by Diagcode. According to the company, their software is designed specifically for people who want to diagnose and repair their Tesla, and they pride themselves on constantly updating it automatically.

They support the Tesla Model X and Model S. Although they also support the Model 3, it would require additional hardware to make it work. If you’re a Model 3 owner, watch their video below on how T-Diag works with your vehicle:

See all Model 3 supported functions starting at 0:15.

Final Thoughts

Aren’t we productive? Not only did we make it clear that Tesla doesn’t have a check engine light because it doesn’t have an engine, but also we were able to cover how we can know if there’s a problem with our Tesla.

If there’s something not working properly as it should, your dashboard’s indicator lights or the troubleshooting alerts on your car’s touchscreen will inform you about it.

There are even diagnostic tools and applications to check your Tesla.
In case you get an error message or any warning sign that won’t go away after following the instructions in your owner’s manual or the DIY guide, it’s time to go to your Tesla app to schedule a service.

Zac Ludicrous

Mechanical engineer by profession. TSLA shareholder before the hype. EV enthusiast all day long. Zac enjoys learning about the future of battery technology, autonomy, and EVs. He considers Tesla Model 3 the most important vehicle of the 21st century -- and is in a quest to improve the ownership experience of every Model 3 owner he possibly can.

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