Category: Workshop Tips

Modern vehicles contain more control modules, sensors and connected systems than ever before. As the amount of data moving through a vehicle increases, diagnostic tools must be able to communicate using newer and faster protocols.

Two terms that now appear regularly in scan tool specifications are CAN FD and DoIP. Both are used for vehicle communication, but they work differently and solve different problems.

For Australian workshops servicing newer passenger cars, European vehicles, commercial vehicles and increasingly complex electronic systems, understanding these protocols can help when choosing a professional diagnostic scanner. Many LAUNCH scan tools in Australia now support CAN FD, DoIP or both, depending on the model, VCI and required accessories.

What Is CAN FD?

CAN FD stands for Controller Area Network with Flexible Data-rate. It is an extension of the traditional CAN communication system that has been widely used in vehicles for many years.

Traditional CAN allows control modules to exchange small packets of information reliably. However, newer vehicles generate and process much more data, so the original CAN format can become a limitation.

According to the official Bosch CAN FD technical overview, CAN FD increases the maximum data carried in one frame from 8 bytes to 64 bytes. It can also switch to a higher bit rate during the data section of the message.

In practical workshop terms, CAN FD allows compatible vehicle modules and diagnostic equipment to exchange more information efficiently while retaining many of the familiar characteristics of a CAN network.

Why Do Newer Vehicles Use CAN FD?

Vehicle networks now need to support systems such as advanced driver assistance, powertrain management, battery systems, digital instrument displays, body control functions and connected safety features.

These systems may exchange more data than older vehicle electronics. CAN FD helps manufacturers manage that increased communication demand without replacing the entire CAN-based architecture.

For a workshop, CAN FD support matters because a scanner that only supports traditional CAN may not be able to communicate correctly with every module on a newer CAN FD-equipped vehicle.

A compatible CAN FD scan tool may be required for:

• Accessing supported control modules on newer vehicles
• Completing full-system diagnostic scans
• Reading and clearing manufacturer-specific fault codes
• Viewing live data from compatible systems
• Running active tests and service functions
• Performing coding or programming procedures where supported

CAN FD support does not automatically mean that every function will be available on every vehicle. Coverage still depends on the vehicle make, model, year, control module and diagnostic software.

What Is DoIP?

DoIP refers to diagnostic communication over Internet Protocol. It allows diagnostic information to travel using IP-based networking, commonly over automotive Ethernet.

The word “Internet” can be misleading. DoIP does not mean that a vehicle must be connected to the public internet for diagnosis. It means the diagnostic communication uses the same underlying Internet Protocol technology found in computer networks.

The official ISO 13400-2 DoIP standard defines communication between diagnostic test equipment and vehicle systems using IP, TCP and UDP. It also covers areas such as discovering a vehicle on the network, establishing a connection and routing diagnostic data through the vehicle gateway.

DoIP can provide a higher-capacity communication path for operations that involve larger amounts of diagnostic data.

Why Is DoIP Important for Workshops?

As vehicle software becomes more complex, workshops may need to transfer larger files or communicate with multiple modules during diagnosis and repair.

DoIP can be useful for supported tasks such as:

• Fast full-vehicle scanning
• Communicating with Ethernet-based vehicle gateways
• Transferring larger diagnostic data sets
• ECU coding or software operations where supported
• Working with newer vehicle electrical architectures
• Accessing modules that require a DoIP connection

The AUTOSAR Diagnostic over IP specification describes how DoIP is integrated into standardised automotive software architecture. This reflects the growing role of Ethernet and IP-based communication in modern vehicles.

DoIP does not necessarily replace CAN or CAN FD. A vehicle may use DoIP to communicate with a central gateway, while individual systems behind that gateway continue to communicate through CAN-based networks.

CAN FD vs DoIP: What Is the Difference?

Feature	CAN FD	DoIP
Full name	Controller Area Network with Flexible Data-rate	Diagnostic communication over Internet Protocol
Network type	Enhanced CAN-based vehicle network	IP-based communication, commonly over automotive Ethernet
Main purpose	Carry more data at a faster rate than traditional CAN	Provide a high-capacity path for vehicle diagnostics
Typical workshop relevance	Accessing modules and diagnostic functions on CAN FD-equipped vehicles	Fast scanning, gateway communication and data-intensive diagnostic procedures
Tool requirement	CAN FD-compatible VCI and software	DoIP-compatible VCI, software and sometimes a separate cable

The two protocols are not competitors. A professional diagnostic tool may need to support both because different vehicles and systems use different communication methods.

Does Every Workshop Need CAN FD and DoIP?

Not every workshop needs these protocols for every job. A workshop mainly servicing older vehicles may still complete most daily work using traditional CAN and OBD2 communication.

However, CAN FD and DoIP support becomes increasingly relevant when a workshop:

• Regularly services newer passenger vehicles
• Works on late-model European vehicles
• Performs full-system diagnostics rather than basic engine code reading
• Handles ECU coding, programming or module replacement
• Wants to expand into newer diagnostic work
• Needs a scan tool that will remain useful as vehicle technology develops

If a vehicle requires a protocol that the scanner or VCI does not support, some modules may be unavailable or certain functions may not operate correctly.

What Does a Workshop Need to Use These Protocols?

Protocol support involves more than the diagnostic tablet itself. The complete setup may include:

• A compatible diagnostic scanner
• A VCI that supports CAN FD or DoIP
• Current diagnostic software
• The correct vehicle cable or adapter
• A stable wired or wireless connection
• A suitable battery support unit for coding or programming work

Some scanners include direct DoIP capability through their supplied VCI, while other models require an additional DoIP cable. Workshops should check the complete product package rather than assuming that every function is built into the tablet.

LAUNCH Scan Tools With CAN FD and DoIP Support

Launch Tech Australia offers several workshop diagnostic tools that support these newer communication protocols.

AUSCAN 4 diagnostic scanner uses the DBSCar VII VCI, which supports CAN, CAN FD and DoIP. An additional cable is required for DoIP communication. It is suited to general workshops that need broad passenger vehicle coverage, full-system diagnosis and room to expand into additional software.

X-431 PRO SE is an accessible professional option for workshops moving beyond basic fault-code diagnosis. Its VCI supports CAN and CAN FD, with an additional cable required for DoIP.

X-431 PAD5 Link supports CAN, CAN FD and DoIP through its Smartlink VCI. It is designed for workshops that need broader vehicle coverage, topology mapping, advanced diagnostics, coding and optional light, medium and heavy-duty capability.

X-431 PAD9 Link supports CAN, CAN FD, DoIP and J2534. It also offers multi-channel high-speed scanning, topology mapping and advanced coding and programming functions, making it suitable for busy workshops and diagnostic specialists.

X-431 EURO TAB III uses a Smartlink C VCI that supports CAN FD, DoIP, J2534, D-PDU and RP1210. It is particularly relevant to workshops handling advanced European diagnostics, programming and wider professional diagnostic work.

What to Check Before Buying a CAN FD or DoIP Scan Tool

When comparing diagnostic equipment, look beyond a simple protocol logo on the product page.

Check whether:

• The supplied VCI supports the required protocol
• A separate DoIP cable or adapter is needed
• The vehicle brands you service are covered
• The required diagnostic functions are available for those vehicles
• Software updates are current
• Coding or programming requires additional subscriptions
• Local technical support is available

A scanner may support CAN FD or DoIP at the hardware level, but actual diagnostic access still depends on the vehicle software and manufacturer implementation.

Why These Protocols Matter for the Future of Workshop Diagnostics

Vehicle diagnosis is moving beyond simple code reading. Workshops increasingly need to work with network gateways, larger data streams, advanced driver assistance systems, electronic module replacement and software-based vehicle functions.

CAN FD helps improve communication within CAN-based vehicle networks, while DoIP provides an IP-based route for faster and more data-intensive diagnostic communication. Supporting both gives a workshop better access to the electronic systems used across newer vehicle platforms.

This does not mean every workshop must immediately replace its existing diagnostic equipment. It does mean that CAN FD and DoIP should be considered when purchasing the next professional scan tool, especially if the workshop expects to service newer vehicles over the coming years.

Final Thoughts

CAN FD and DoIP are two important automotive communication technologies, but they serve different purposes.

CAN FD extends traditional CAN communication by allowing larger data payloads and a faster data phase. DoIP uses IP-based networking to create a higher-capacity diagnostic communication path, commonly through automotive Ethernet.

For Australian workshops, the practical question is not which protocol is better. It is whether the diagnostic scanner, VCI, software and cables support the vehicles entering the workshop.

Before choosing a scanner, review the vehicle coverage and protocol requirements carefully. You can also use the Launch Tech Australia support resources or speak with the team through the online enquiry page for product and compatibility advice.

Bi-directional control is one of the most useful functions in a professional automotive scan tool. It allows a diagnostic scanner to send commands to a vehicle system, not just read information from it.

In simple terms, a basic scan tool can listen to the vehicle. A scan tool with bi-directional control can also talk back to the vehicle.

For Australian workshops, this function can make diagnostics faster and more accurate. Instead of only reading a fault code and guessing what might be wrong, technicians can use active tests to command certain components, observe the response and confirm whether a system is working as expected.

Many professional LAUNCH scan tools Australia support bi-directional control, also known as active tests, depending on the vehicle, system and software coverage.

What Does Bi-Directional Control Mean?

Bi-directional control means two-way communication between the scan tool and the vehicle’s control modules.

With normal diagnostics, the scanner receives information from the vehicle. This may include diagnostic trouble codes, live data, freeze frame data or module status. With bi-directional control, the scanner can also send a command to the vehicle module and ask it to perform a specific action.

For example, a technician may use the scan tool to command a cooling fan to turn on, activate a fuel pump relay, cycle an ABS pump, operate an EGR valve, trigger an EVAP purge solenoid or test an electronic parking brake function.

This helps the technician check whether the component, wiring, module command and system response are working correctly.

Why Is Bi-Directional Control Useful?

Bi-directional control is useful because it helps workshops test systems without relying only on fault codes.

A fault code can point the technician in the right direction, but it does not always tell the full story. A code may relate to a sensor, actuator, circuit, module, voltage issue or communication problem. Active tests can help narrow down the cause.

For example, if a cooling fan does not operate during normal driving, a technician can use a scan tool to command the fan on. If the fan responds, the motor and circuit may be capable of working, and the issue may be related to temperature input, control logic or another condition. If it does not respond, the technician can continue checking power, ground, relay operation, wiring or the fan assembly itself.

This can reduce guesswork, save diagnostic time and help avoid replacing parts unnecessarily.

Common Active Tests Workshops May Use

The available active tests depend on the vehicle make, model, system and scan tool coverage. However, common examples may include:

• Turning cooling fans on and off
• Activating fuel pumps or fuel pump relays
• Testing EVAP purge and vent solenoids
• Operating EGR valves or throttle actuators
• Commanding ABS pump or solenoid tests
• Testing electronic parking brake operation
• Activating injectors or ignition-related functions where supported
• Operating door locks, windows or body control functions
• Testing air conditioning clutch or HVAC actuators
• Running selected DPF, battery, steering or service-related procedures

These functions are especially helpful when diagnosing intermittent faults, electrical faults, actuator issues and system communication problems.

Bi-Directional Control vs Live Data

Live data and bi-directional control are often used together, but they are not the same thing.

Live data shows what the vehicle is reporting. For example, a technician may view coolant temperature, oxygen sensor readings, fuel trims, wheel speed data or battery voltage.

Bi-directional control allows the technician to command an action. For example, the scanner may ask a component to switch on, open, close, cycle or perform a test.

Used together, these functions are powerful. A technician can command a component and then watch the live data response to confirm whether the system reacts correctly.

Bi-Directional Control Is Not the Same as Coding or Programming

It is also important to understand what bi-directional control is not.

Bi-directional control is mainly used for testing and commanding components during diagnosis. Coding and programming are different functions. Coding may change configuration or adaptation settings, while programming may involve writing software or data to a module where supported.

Some advanced diagnostic tools support bi-directional control, coding and programming, but they should not be treated as the same function. For most workshops, bi-directional control is a practical day-to-day diagnostic feature, while coding and programming are more advanced procedures that require extra care, correct information and stable workshop conditions.

When Should a Workshop Use Bi-Directional Control?

Workshops may use bi-directional control when they need to confirm whether a component or system can respond to a command.

Common use cases include:

• Checking whether an actuator works before replacing it
• Confirming whether a control module can command a component
• Testing wiring, relays and power supply paths
• Comparing commanded action with live data response
• Running post-repair checks after replacing parts
• Verifying service functions after maintenance work

This is especially valuable for modern vehicles, where multiple systems may interact with each other. A simple warning light may involve engine, transmission, ABS, body control, steering or ADAS-related systems.

What Are the Limitations?

Bi-directional control is powerful, but it is not available for every function on every vehicle.

Availability depends on the vehicle manufacturer, model, year, system, control module, software coverage and diagnostic tool capability. Some vehicles allow many active tests, while others provide limited command access. Some functions may also require special conditions, such as correct battery voltage, ignition state, engine temperature, gear position or safety requirements.

Technicians should always follow safe workshop procedures when using active tests. A commanded component may move, switch on, build pressure, activate a motor or change vehicle behaviour. The vehicle should be secured, the work area should be clear and the technician should understand what the function is expected to do before running the test.

Which LAUNCH Scan Tools Support Bi-Directional Control?

Many professional LAUNCH X-431 scan tools support bi-directional control, depending on the model and vehicle coverage.

For workshops looking for a capable all-round diagnostic tool, the AUSCAN 4 supports full-system diagnostics, bi-directional control, service functions, coding and guided functions, with optional software expansion for workshops that want more flexibility.

For entry-level technicians or workshops looking for professional functions, the X-431 PRO SE includes full diagnostic functionality such as reading and clearing DTCs, live data streaming, bi-directional control, remote diagnosis and coding.

For workshops that need a more advanced professional tablet, the X-431 PAD5 Link supports full-system diagnostics, topology mapping, bi-directional control, coding, programming, service functions, ADAS-ready capability and optional extended modules.

For high-end workshops wanting flagship performance, the X-431 PAD9 Link offers advanced functions including bi-directional control, topology mapping, high-speed system scanning, SGW access, live data graphing and optional commercial vehicle and new energy vehicle coverage.

For workshops that work across both passenger vehicles and trucks, AUSCAN Smart is designed for car and truck diagnosis, with functions such as read/clear DTCs, live data streaming, bi-directional control, coding and programming.

How to Choose a Scan Tool With Bi-Directional Control

When choosing a scan tool with bi-directional control, do not look at the feature name alone. Look at how the tool fits your workshop’s real work.

Consider these questions:

• What vehicle brands do you service most often?
• Do you need passenger vehicle, commercial vehicle or heavy-duty coverage?
• Do you need full-system diagnosis, or mainly engine and service functions?
• Do you need active tests only, or also coding, programming, ADAS, TPMS or EV support?
• How important are software updates and local technical support?
• Will the tool support the type of diagnostic jobs you want to take on in the future?

Modern workshops also need access to accurate service and repair information. In Australia, the ACCC Motor Vehicle Information Scheme explains how Australian repairers can access service and repair information, while the Australian Automotive Service and Repair Authority provides access pathways for manufacturer repair information.

Final Thoughts

Bi-directional control is one of the key differences between a basic code reader and a professional workshop diagnostic scan tool. It allows technicians to command vehicle components, run active tests and confirm system response during diagnosis.

For Australian workshops, this can help reduce guesswork, improve diagnostic accuracy and support more professional repair workflows. Whether you are checking a cooling fan, testing an ABS function, confirming an actuator response or completing post-repair checks, bi-directional control gives technicians more control over the diagnostic process.

If your workshop is comparing diagnostic scanners, choose a tool based on vehicle coverage, active test capability, service functions, software updates and local support. For help selecting the right scan tool, contact the Launch Tech Australia team.