What is the CAN BUS BOX with an Android Head Unit?

‘CAN BUS BOX included’ is featured in many of the Android Head Unit advertising features.

• What is the CAN BUS BOX for?
• What even is a CAN BUS?
• Do I need the CAN BUS option for my android head unit to work?
• Does my car have a CAN BUS?
• One CAN BUS BOX for all cars?

CAN BUS BOX Confusion

CAN is short for the Controller Area Network, but it can also be referred to as the Car Area Network. This is because this network is designed to allow for the various computers installed into vehicles to communicate with each over.

BUS is a communications cabling system

So a CAN BUS is the communications network designed for in vehicle applications.

CAN BUS BOX is a communications device box that interfaces with the CAN BUS in your vehicle. This is used by the android head unit to get information that is travelling on that BUS. This information can be anything from the vehicle speed, the battery voltage to the settings on the climate control panel. All of these and many more are available on the vehicle CAN BUS.

Custom fit

A CAN BUS BOX will typically be an optional extra or an included option for a custom fit android head unit. The CAN BUS BOX option is an ideal reason to get a custom fit android head unit that is not only tailored to fit well, connect with factory connectors, it can connect to the vehicle CAN BUS for all those added features.

Universal fit

Universal fit android headunits won’t come with a dedicated CAN BUS BOX because being universal, there is no way of knowing which car it will be fitted into. Not all cars are CAN BUS enabled, particularly older models that pre-date the CAN BUS design. These may use a proprietary BUS that is incompatible with CAN. If you are looking for CAN BUS integration in an android headunit, look for a custom fit that supports the features you want. While some universal android head unit will connect to a CAN BUS BOX, finding one is not so easy and getting the software into the head unit to communicate with the box is challenging.

Features

If your vehicle is CAN BUS compatible and a CAN BUS BOX is available for it, then the correct android headunit will be able to read all the CAN information. This can, as already mentioned, be vehicle speed, battery voltage, lights on/off, reverse gear selected, handbrake/emergency brake applied, air conditioning control positions, doors open/closed, steering wheel controls (SWC) or any number of other CAN signals that the CAN BUS BOX can decode.

Typical CAN BUS BOX listings confirm these features

• Support steering wheel buttons to control Android radio
• Support the display of door status and fuel consumption on the Android radio
• Support the car’s original 360 panoramic image control
• Support car original power amplifier control
• The temperature shows on the Android Headunit

No CAN BUS BOX

If you don’t fit the CAN BUS BOX or there is not one available for your vehicle, the connections to ‘reverse gear‘ (for backup camera), ‘headlights on‘ and ‘steering wheel controls‘ (SWC) will need to be made in alternative way to allow the headunit to function to its full potential. You won’t be able to get air conditioning information or even battery voltage without a CAN BUS connection.

Vehicle Specific

The CAN BUS BOXes are vehicle specific. While car manufacturers re-use many of the parts and designs of parts in their models, including the internal networks there can be subtle differences. The advantage of computers in cars is that it only takes a software change in a part to make it suitable for a different application. For example, the body control computer for the 2 door model is the same as the 5 door model, just with different software settings. But that body control can be used across several models too, with some subtle changes. The CAN BUS BOX will need to be programmed to communicate with the CAN BUS and the different controls in the car. If a car manufacturer makes a software change on a production run, this can throw the CAN BUS BOX compatibility into a mess.

Enter CAN BUS settings

Common problems

CAN BUS BOX common problems come down to compatibility and configuration.

You are lucky if it is just a configuration problem that just needs a different selection in the CAN BUS App or a dip switch setting on the actual CAN BUS BOX. A typical can bus configuration problem is Driver door open, the screen shows it as the passenger door! and the solution is in the post. Or you want the ‘Battery icon showing on Android Head Unit Screen‘ and just need to enable it (solution in that article).

Not so easy to solve are the ‘Air conditioning controls not showing/working’ problems. This is where the android headunit should read the A/C control positions, including fan, temperature, split etc. But the CAN BUS BOX or the android app is not able to read the CAN BUS information. It may still be due to a configuration issue, so check the correct vehicle is set in the app, then try other vehicle variants in the app. When all of that is exhausted it will most likely be a compatibility problem. Reach out to the vendor for assistance, but if they don’t have the solution, they can’t help.

Replacement CAN BUS BOXES

You many need a replacement CAN BUS BOX for your android headunit. If you change your vehicle and install the headunit in a similar model would be one reason. Maybe you have treated yourself to the later model that is a bit newer and has a few extra features. If the dashboard aperture is the same, then it may just be a case of adding a newer CAN BUS BOX. You may find your CAN BUS BOX just stops communicating. Or you want to diagnose the faults with a different CAN BUS BOX. The good news is you can get replacement CAN BUS BOXES for the android head units, on Ali Express. It takes a bit of searching because the CAN BUS BOXES are very vehicle specific. The vehicle physical connectors and the CAN BUS decoding software inside the box are model specific. Take your time to select the correct model for your use.