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Investors Relations & Haldex information

EB+4.0: be safe and secure

30 March 2022

Haldex’s new EB+4.0 for heavy duty trailers now provides parking brake safety and security features. 

New hardware EB+4.0 includes redesigned solenoids that are smaller, more robust but lighter than before. In addition, the system is also lighter, as it is now constructed from engineering-grade polymer. Four different versions are available: a basic EBS with two modulators and two wheel speed sensors with no emergency brake override; a basic EBS with emergency brake override; a premium EBS with two additional electrical interfaces, which can be extended to eight sensors and four modulators; and an additional modulator, which is used to map larger systems. As standard, EB+4.0 comes in a 2S/2M configuration suitable for fitment to three-axle semi-trailers. The system can be extended up to 8S/4M, consisting of one master, two slaves and up to eight wheel speed sensors. Such configurations would be suitable for a 10-axle low-loader. For road trains, an additional EB+ CAN Hub block linking two EB+4.0 systems is also available.

The system has been in development for seven years. Some 150 pre-production units are being made available to trailer-builders for type approval; it already has a high-profile by one of the big trailer builder in Europe.


EBS systems, such as Haldex’s current EB+ Gen 3 system, rely on solenoids (to control pressure modulators) in a central valve bank that respond to electronic signals to either increase or decrease air pressure in an air brake circuit to either apply or release the brakes. Its EB+4.0 system maintains that design for service brakes, and, thanks to a new optional valve bank, extends electronic control for the first time to the parking (spring) brake side of the double-diaphragm brake actuator.

This allows much better control of the airflow of the parking brake and through the electronic control we generate added value by increasing the safety for the operators. Previously, connecting the red Suzie coil between truck and trailer would automatically release the parking brake if the red knob of the park and shunt valve is not activated. Now, the system provides additional control of that process, via the EBS ECU (electronic control unit) and an extra solenoid valve.

First, this connects the parking brake release command to other local or remote microprocessor-controlled systems for additional security checks, to prevent theft or misuse of the trailer. The trailer could compare the VIN of the tractor it has been hitched to, to a white list of approved tractors, before releasing the brake. Or it might remain locked in place until transmitting its location to, and receiving approval from, a telematics system, to make sure it has not been taken outside of its authorised area. Alternatively, the ‘go’ signal might come direct from head office (although semi-trailers with parking brakes fitted with conditional control do not require continuous power, they do require an electrical connection from the tractor).

These are just a few examples and by no means exhaustive; such functions must be programmed into the system via a new application programming interface (API). Haldex is quite flexible when it comes to implementing such modifications. On behalf of the customer, the company can develop customised functionalities or incorporate customer functions into regular software updates, and by the same token, a customer-specific release plan can also be agreed. This process is now much simpler than before, because a change in software system architecture further separates safety-related brake control features from customer-specific application programming interface (API). That means that it is potentially easier to make changes and maintain the overall safety of the system with EB+4.0.

The second new feature is an enhancement of the existing Safe Parking system, which provides extra safety when coupling and uncoupling. Safe Parking+ will not release the parking brake until the system detects a safe condition: that the air brake system is fully pressurised, and the driver has depressed the service brakes or the service brake is applied by the trailer control valve of the truck. That means that the air coils have been connected (and in the correct order), and that the driver is back in the cab. This increases the protection of roll-away incidents compared to the previous Safe Parking system, which would only release the semi-trailer brake when the driver pressed a lever mounted to the side of the vehicle. In addition, it prevents the possibility of roll-away if the combination were parked on a grade and the driver forgot to apply the tractor parking brake, or if it were on a grade and the driver attached the coils in the wrong order.

The third feature, emergency brake override, is not in fact new; it was a feature on Haldex EB+ Gen1, and has been reintroduced. It comes as standard with most EBS variants, and blocks emergency application of the parking brake when the vehicle is moving (by reading input from the wheel speed sensors). This is perfectly legal. ECE R13 safety regulations stipulate that if the energy supply between truck and trailer is lost, the trailer must apply emergency braking. This could be via the parking brake, as has been the case with previous versions. While this will bring the truck and trailer to an almost immediate halt, during that process the trailer wheels will lock, destroying the trailer tyres and threatening those vehicles travelling near the vehicle.

But the safety regulation also allows emergency actuation via the trailer service brakes. That offers several advantages, the least of which is that braking can be controlled by ABS protection. A greater advantage is that this option facilitates the use of the emergency brake override system.
If the emergency brake override detects that the energy supply has been disconnected or lost, but if there is sufficient air pressure in the system to operate the service brakes, it will do two things: trigger a red warning light in the cab, and override immediate actuation of the brakes. During this time, the driver will be able to use the existing air pressure to operate the service brakes as normal to stop in a controlled manner at the nearest possible opportunity. Such manoeuvres depend on an intact electrical connection between tractor and trailer. Once the truck reaches a lower brake pressure threshold, the emergency braking system applies the spring brake, as the regulations require.


For trailer-builders, vehicle operators and their technicians, Haldex offers new DIAG++ PC software to support operation of EB+4.0. This not only offers a fresh look to a familiar interface (designed in Microsoft.Net), but also integrates three previously-separate software packages under one umbrella. Diagnostic module inputs vital parameters such as the number of axles, weight and centre of gravity to configure the braking system. Fleet+ offers access to operational data, such as the number of braking applications, the rate of deceleration, mileages, durations, and provides standard reports of this information for fleet managers. Finally, a service module allows updates of EBS firmware. (Although the software is offered free of charge, PC connection to EB+4.0 is via proprietary USB dongle and connector).

All EBS units and peripheral devices communicate via the new diagnostic communication protocol UDS (Unified Diagnostic Services) in the automotive sector and are thereby replacing the previous Keyword 2000 protocol. This change also contributed to the design of a technologically-sustainable system.


In short 

  • Telematics controlled remote brake release safeguards isolated semi-trailers; Safe Parking+ safety feature prevents roll-away during coupling and uncoupling from optional Mobiliser module; emergency override feature gives driver time to make a controlled stop before emergency brake application
  • Innovative software architecture separates safety-related functions from user application software to allow API development, customisation and functionality upgrades without requiring new type approval
  • Fourth-generation brake controller is lighter and more robust than previous generation, updated with latest communication protocols, and offered with new DIAG++ set-up, fleet management and service software
  • Launch customer is one of the big trailer builder in Europe; series production begins in December


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