DONT BE DAFt: LETS TALK ABOUT FRAME CAN

FRAME CAN FUN

Sorry bit of a long one in this week's waffle, as it will be about the advancements from euro 6 to model year 17 which I touched on at the end of my video anyway let's talk about the components involved in making this happen.



Frame CAN or F-CAN to the uninitiated, is yet another system to go wrong in some people’s eyes, yet the ability to operate inputs and outputs at the rear of the vehicle with only two wires is AMAZING!

VEHICLE ELECTRONIC CONTROL UNIT

We will start at the front of the truck in the cab where VECU is located.


The centre of all vehicle data communication and the location of key control operations is the VECU (Vehicle Electronic Control Unit). 

The vehicle cannot be driven if the VECU is not operational. DAF introduced VECU to vehicles from specification week 2 2017-25.

VECU replaced VIC-3 (vehicle intelligence centre) and the CSM (cabin switch module) which I won't talk about today as we don't have all day! 

The VECU's primary duties are:

  • function of network and data management.

  • monitoring and controlling cabin switches.

  • Some bodybuilder and power train roles for the truck.

  • inside and outside lighting operations.

  • monitoring of sensors and actuator control (directly or via chassis modules)

Most cabin switches, as well as numerous control operations, are dependent on a functioning VECU, such as The Cabin Switch Module, Chassis Module Front and Chassis Module Rear, which we will get into now.

CMF AND CMR CHASSIS MODULES


The modules are mounted at the front and rear of the vehicle. Their main job is to act as an interface between F-CAN and other (non-CAN controlled) vehicle parts. 

A chassis module serves as the VECU's "do-ers" (the VECU controls the modules and only processes the signals from VECU into an output. The modules don't "think").

All outputs and inputs are safeguarded against overloading, open circuits, short circuits and as such will produce a DTC for these faults….. which is nice 🙂

The modules will restart once the error has been resolved.

One of the major advantages of this system is the complexity, length, and weight of the truck wiring are all decreased with the development and fitment of the chassis modules

With the introduction of these modules, DAF also added safety features known as "limp home mode" which was EXACTLY what happened at the start of my video, As the lights were flashing on and off due to the CAN communication issue.

This feature automatically activated the following outputs during a communication failure on both modules:

  • Dipped beam

  • Marker lights

  • Rear lights 

WHAT ABOUT YOUR OTHER LIGHTS!

The Brake light and the Hazard warning light functions can still be activated normally. 


This is accomplished by using emergency hard-wired inputs on the chassis modules from the VECU and the EBS ECU

Just when you think it's just the can wires that work these ECUs....it isn't! 

SMART AIR CONTROLLER

Last but not least is the SAC, this is mounted in the middle of F-CAN 


We abbreviate the smart air control system as SAC. With its electronic intelligence, data from pressure sensors and the vehicle's CAN are used to manage the precise distribution of compressed air and to provide optimal control of the brake system.

 

the SAC combines the functions of an air dryer and a multi-circuit protection valve with electrical monitoring of system air pressure.

Another advantage of the sac is that additional air reservoir for the trailer/park brake can be omitted due to the intelligent control..... fancy! 

In the event of a fatal electrical failure, SAC automatically switches to load mode, maintaining pressure while providing warning information to the driver as in its fucked 

So this sums up our frame can and I know I've most probably missed out on the finer details of the modules but this is a blog not a manual after all....…and yes I'm still writing it which will be available soon! 

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