Modern cars and trucks contain many electronic control units that run the engine, monitor vehicle functions and manage other systems, and these units need to share information to work together. So what is CAN bus? It is one of the communication technologies used inside vehicles to exchange data between those control units, and some of that data can also support fleet tracking, fuel monitoring and engine-hour reporting.
This guide explains what CAN bus is, how it works, how it differs from GPS and OBD, which CAN bus data fleets can use, and when you need a compatible device or interface to read it.
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What Is CAN Bus in a Car or Truck?
CAN bus stands for Controller Area Network. It is a communication system that lets the electronic control units (ECUs) inside a vehicle exchange messages over a shared network, instead of running a separate wire for every signal between every system.
A vehicle has several ECUs with different jobs. One may manage engine functions while others handle the transmission, the brakes or comfort equipment, depending on the vehicle’s design. The CAN network lets these units exchange the messages they need, according to the protocols and signals used in that vehicle.
CAN bus is not a GPS tracker. It is an internal network whose data some tracking solutions can use, and the data available differs from one vehicle to another.
How Does CAN Bus Work?
- Collecting information: each ECU receives readings from the sensors and systems connected to it.
- Sending messages: ECUs broadcast structured messages on the network. The protocol handles message priority and detects some communication errors.
- Receiving data: the units that need a message receive it and use it according to their function.
- External use: compatible devices or diagnostic tools can access specific data. In fleet tracking, a compatible tracker may read some values and send them to a monitoring platform.
Heavy vehicles such as trucks and buses commonly use the SAE J1939 standard, which runs on top of CAN and defines how many engine and vehicle parameters are reported. Even so, access to CAN bus data does not mean every piece of information in the vehicle becomes available to a tracker.
What CAN Bus Data Can Fleets Use?
What you can read depends on the vehicle make, model and year, its control units, and the capabilities of the device or interface. Examples that may be available:
- Fuel level or consumption: available in some vehicles through a compatible interface. If not, a separate fuel sensor may be needed.
- Odometer: distance from the vehicle’s own source, useful for maintenance and reports once verified.
- Engine hours: helpful for reviewing equipment use and planning maintenance.
- Speed and operating status: depending on what the vehicle, interface and device allow.
- Engine temperature and other values: in certain vehicles. Cargo temperature in a refrigerated truck is a different need that usually requires a dedicated temperature sensor.
The basic rule: having CAN bus in a vehicle does not guarantee that every value you want is available. Verify the actual data the device and vehicle support before you start.
CAN Bus vs GPS
People often mix the two because they are used together in tracking solutions, but each has a different job. GPS determines the vehicle’s geographic position from satellite signals. CAN bus is a network inside the vehicle for exchanging data between control units. Many trackers combine both: GPS for location, plus selected vehicle data, so the platform shows where the vehicle is and how it is operating.
CAN Bus vs OBD
CAN bus is a communication system, while OBD refers to the vehicle’s on-board diagnostics and the diagnostic port used to access standard information. Many vehicles carry OBD data over the CAN protocol, but the two terms are not the same. Having an OBD port also does not mean that all CAN bus or engine data is available through it.
How CAN Bus Data Is Used in Fleet Tracking
- Define the data you need: fuel, distance or engine hours, based on your operations.
- Check compatibility: confirm the vehicle provides the data and the tracker can read it in a supported way.
- Install and configure: a qualified technician fits and sets up the device according to approved instructions.
- Send to the platform: available values are shown next to location and trip data.
- Review: authorized users check readings and use them in reports.
Avoid improvised wiring that could affect vehicle systems. Our CAN Bus vehicle data solution covers this assessment and setup.
CAN Bus and Fuel Monitoring
Fuel information may come from the vehicle itself when it is available through a compatible interface. If no suitable reading exists, a dedicated fuel sensor is needed. The choice depends on the vehicle, the data available and the accuracy you require; see fleet fuel monitoring. And remember that not every drop in a fuel reading proves theft, so check the data source and operating conditions first.
Does Your Company Need a CAN Bus-Based Solution?
It makes sense when you need operating data beyond location, for example:
- Fuel data available through a supported interface.
- Engine hours for equipment and maintenance planning.
- Reports that combine location with selected operating values.
If your main goal is knowing where vehicles are and reviewing their trips, you may not need CAN bus data at the start.
How to Choose a Tracker That Reads CAN Bus Data
- List the exact data you need rather than asking for “CAN bus support” in general.
- Confirm vehicle compatibility in writing for each make and model.
- Check the interface: some data needs a specific reader or adapter.
- Check the platform: the tracker may receive a value, but the platform must also display and report it.
- Test before rollout: verify readings on a few vehicles first. For a practical example, read our Teltonika CAN bus guide.
Frequently Asked Questions
What does CAN bus stand for?
CAN bus stands for Controller Area Network, a technology that lets the electronic control units inside a vehicle exchange messages and data over a shared network.
Is CAN bus the same as GPS?
No. GPS determines location, while CAN bus is a network inside the vehicle. Some tracking systems use both to provide location plus selected operating data.
Is CAN bus the same as OBD?
No. CAN bus is a communication technology, while OBD refers to on-board diagnostics. Some diagnostic interfaces use the CAN protocol, but they are different terms.
Can fuel level be read from CAN bus?
In some vehicles, yes, if the fuel reading is available through a compatible interface. In others, a dedicated fuel sensor is needed.
Does every GPS tracker read CAN bus data?
No. It depends on the tracker, the interface, the data required and its compatibility with the vehicle.
Do I need CAN bus for vehicle tracking?
Not necessarily. If you mainly need location and trip history, standard tracking is enough. CAN bus becomes useful when you need extra operating data.
How Afaq Alrasd Aldhki Can Help
We help companies in Saudi Arabia work out which vehicle data they really need, check what each vehicle and tracker can provide, and show it on Afaq Platform next to location data, with installation and technical support. Explore CAN Bus vehicle data, or request a quote to discuss your vehicles.
