What is CAN Bus?

CAN Bus is a multiplexed wiring system used to connect intelligent devices such as Electronic Control Units (ECU's) on vehicles, allowing data to be transferred in a low-cost and reliable manner. CAN means 'Controller Area Network' and was developed by Bosch in 1980. Most new vehicles use this system and it is becoming increasingly difficult to install after-market products without using a CAN Bus Interface.

Why is this system used?

The reasons for the vehicle manufacturers using CAN Bus are:-

(a)  Significant reduction in wiring leading to:-

      (i) Significant reduction in manufacturing cost and hence retail cost.

      (ii) Reduction in weight resulting in improved fuel consumption.

(b) Reduced number of interconnections hence improving reliability.

How can I find the CAN Bus Wires?

It is easy to identify the wiring as it is just a twisted pair of thin wires. These will be found all over the vehicle - sometimes in with a conventional main loom. The wires are called 'CAN High' and 'CAN Low' and it is important that any interface is connected correctly to these wires. All Bridgwater Electronics Interfaces have an LED to indicate when the wires have been connected correctly.

What aftermarket products will require a CAN Bus Interface?

Most of the higher specification GPS Navigation systems will require a speed pulse signal as a minimum. Many also have inputs for illumination and reverse signals. On CAN Bus vehicles these signals may not be present so a CAN Bus Interface will be required.

Taxi Meters require a speed pulse signal in order to calculate the fare. Hence on CAN Bus equipped vehicles, a CAN Bus Speed Pulse Interface will be required.