Fitting aftermarket kit to an older van meant finding the right wire. You tapped the reversing light feed for a camera, an ignition live for a tracker and an indicator wire for a beacon. On a current model a lot of those wires are no longer there in any form you can safely tap. Reverse gear, ignition state and the lights are messages on the CAN bus, carried on a shared twisted pair, and the dedicated feed you were expecting may not exist at all.
So the method changes. Rather than splicing into a circuit, you read the signal off the bus and use it to switch an output of your own. A CAN interface module is the part that makes that possible.
The trouble with splicing
Cutting into the native wiring on a modern vehicle is a gamble. The circuits run at low current and the body controller watches them closely. An extra load or a poor joint can set a fault code, put a warning on the dash or upset another system that shares the same module. Piercing the CAN pair itself is worse, because a bad joint there can corrupt traffic for every module on that bus.
Warranty is the other issue. Converters and fleet operators who return vehicles at the end of a lease, or keep them under a manufacturer contract, do not want to explain a row of Scotchlok connectors to a dealer. And even where a usable feed exists, it was never rated for the extra load you want to hang off it.
Reading the bus avoids every one of those problems. The vehicle’s wiring is left exactly as it left the factory, and your equipment runs from an output you control and fuse yourself.
Wired or contactless
There are two practical ways to connect an interface to CAN.
A wired connection goes to the CAN high and CAN low lines at a known access point, often the OBD socket or a body control module connector. Where that point is documented for the vehicle, it is the quickest install.
A contactless connection uses an inductive reader that clips around the CAN wires and picks up the traffic without cutting or piercing the insulation. The loom is untouched, which is why it is the one to use on a vehicle still under warranty. Both i2CAN modules have a 5V protected output to power an inductive reader such as the CAN croc, so a no-cut install needs no extra supply.
What the module does with the data
The interface listens to the bus and ignores most of what it hears. It is configured to pick out the handful of states the job needs, such as reverse selected, ignition on, sidelights on or road speed above a threshold. When one of those changes, it switches an output. That output might drive a relay, power a camera, arm a parking sensor or feed a telematics input.
The i2CAN-8 is our standard module. It reads two isolated CAN lines and has eight switched outputs good for 900mA each (two of the eight switch negative), which is plenty for a whole conversion from one box. The i2CAN-4 is for simpler single-line jobs and has four outputs. Both run on 12V or 24V, let you set the baud rate up to 1 Mbps and handle 11-bit and 29-bit identifiers, so the same hardware covers cars, vans and trucks.
When one bus is not enough
Some vehicles split their functions across more than one network. Reverse might be on the powertrain bus while the lighting states live on a body bus. The i2CAN-8 reads both lines independently through its two isolated CAN peripherals and can drive any output from either. Without that, you end up with two or three single-function boxes behind the dash, each needing its own supply and each a separate thing to fault-find.
If you would rather order by job than by hardware, the CAN KONTROL range supplies the i2CAN platform already configured for a task. CAMERA, for example, gives a reverse trigger for camera and monitor systems.
New models and facelifts
CAN messages change when manufacturers release new models and facelifts, so a module configured for last year’s van may not read this year’s. There are two ways to deal with that. The budget i2CAN modules go back to the factory for a signal upgrade. The premium version has USB OTG, so you can reprogram it in the field. Either way, when a fleet changes vehicles the modules can be reconfigured and fitted to the new ones instead of being thrown away.
We design and build every i2CAN module in the UK.
If you are not sure which bus carries the signal on your vehicle, send us the make, model and year along with what you want to switch, and we will come back with the module and setup to use.