5 reasons why Toyota DCM not working

The modern Toyota vehicle is expected to connect to the internet and has a built-in GPS, all for the convenience of the driver. If the internet is not available, then the DCM in a Toyota vehicle is not working. It is usually because of a software glitch, or the free trial has expired.

Why is my Toyota’s DCM not working?

Most modern cars now have internet capabilities. That only does the internet connect with satellites in the sky for the GPS navigational unit, but there’s also a secondary internet communications system that creates Wi-Fi inside the car.

Without internet capabilities and Bluetooth, cars are not able to sync up with their driver’s phones.

Toyota has its own unique type of internet technology for its vehicles, and it is called DCM. DCM stands for Digital Communication Module. Some services are standard with the vehicle and other services require a yearly subscription.

Most drivers use the DCM system in their vehicles at least once a day. But what happens when the Toyota DCM is no longer working, and an error sign is flashing on the console screen?

There are 5 common reasons why a Toyota vehicle DCM system would stop working. Those reasons are:

● The DCM software needs to be updated – the DCM system runs on software and like your computer software, it will need to be updated from time to time. Depending on the DCM service in your existing vehicle, an update could be postponed or it has to happen right then and there. Some Toyota vehicles will not allow the DCM services to be used until the update is complete.

● The wire that powers the DCM unit is damaged – the DCM unit is attached to a wire and that wire carries electricity to the unit. A number of reasons why the wiring is damaged, including faulty installation by the manufacturer or coolant leaking on the wire.

● The head unit is not working and it does not know that there is an issue – Loss of connection with the head unit is a major problem with all Toyota vehicles. No matter what type of service you use, the paid or the standard, you will have an issue with the head unit. Losing connection with the head unit is such a prevalent issue with Toyotas. You can find someone complaining about head unit issues in every Toyota nation forum.

● You did not renew the paid services – while all Toyota vehicles come with a few standard services, you can pay a yearly service fee and get the upgraded package. However, be sure to pay for the yearly service! Some people forget that they’re using the paid trial and then the trial runs out.

● The fuse behind the DCM is burned out – This fuse is known as the DCM fuse and it is usually behind or below the DCM unit. 

Will my Toyota work without the DCM services?

Technically yes. You’ll be able to drive your car if the DCM services do not work. You’ll be able to open and close the trunk, use your fob key to open the car from a couple of yards away and you also be able to use the air conditioner.

You won’t be able to use the GPS navigation system on your vehicle. You also cannot use hands-free calling via Bluetooth to connect your phone to your car. Any of the internet or telecommunication services will be off-limits until you fix the issue or update the software. 

This includes paid Services as well. It will not matter if you have a monthly or yearly subscription to a service, if the DCM unit is not working, you want to have access to the services.

How to fix my Toyota’s DCM

Fixing your Toyota’s DCM is not a technique that most people know how to do. Even experienced drivers don’t know how to fix their vehicle’s computer systems. So you will have to rely on the Toyota service center.

Software update – You should be able to enable the software to download the update directly from the vehicle. You may not be able to update it when you drive, so wait until you get home

Glitching Head Unit – Fixing your vehicle’s DCM software and other computer programs in the head unit is not recommended if you don’t know what you are doing.

Also, it may not be a good idea to take your Toyota vehicle to your regular mechanic to fix this type of issue. For DCM issues, you will need to go to a Toyota-certified service center.

When you arrive at a Toyota Certified service center, they can use their diagnostic tools to run through the codes and find out why the DCM is not working correctly.

Fuse Issue – The DCM fuse is usually behind or underneath the DCM unit. Some models will be able to access the DCM fuse and the relays when they open the backing to the glove compartment. 

There are multiple fuses in the area, so you will have to take out each fuse and replace it with a new one until you find the one that is blown.

If you still have your owner’s manual, you can use the DCM fuse and relay diagram to help you locate the fuses that connect to the DCM unit. 

If this sounds like too much of a hassle, you can always send your vehicle to the Toyota service center. 

You can also use a multimeter to find the fuse that is no longer working. Using a multimeter is easy, even if you have never done it before. 


The DCM unit inside a Toyota is used to connect the vehicle’s computer system with internet and GPS navigation, along with a few other paid services. If you see a DCM ERROR or a similar warning flashing on your console screen, then the fuse or wires may have blown.

A few other reasons why the DCM many now work is that it needs a software update, the computer is glitching and needs to be reset, or the head unit is no longer working. 

  • Eric Williams

    I'm the founder of Daily Car Tips. I wrote articles in the automotive industry for more than 10 years, published in USA and Europe. I love sharing my knowledge and insights with fellow enthusiasts. Join me on this journey as we explore the exciting world of cars together!

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