How can I tell the vehicle is CANbus or not?
Posted by Matthew Yu on Fri, Oct 16, 2009 @ 11:16 AM
The Federal Government mandates that all MY2008 or newer vehicles must be equipped with CANbus system. However, some makes and models have already been equipped with CANbus as early as 1999. Since most aftermarket repair
shops will service vehicles between 1999 to 2008, it is very useful for technicians to be able to identify whether is the vehicle is CANor not, especially when using OE-level scan tool diagnostics as it can save significant amount of time on navigating the scan tool menu.
CANbus, which stands for Controller Area Network Bus, is a data communication network installed on the vehicle to speed up communication between computers (ECUs) and electrical components inside the vehicle. As more and more sophisticated electronics and computers are being added to the latest vehicles, CANbus system can improve vehicle performance by increasing the data transfer rate and hence shorten the sensors and actuators response time. In addition, CAN only require each control module a twisted pair of electrical wires connected to the data bus and thus significantly reducing number of electrical wires needed to be installed on the vehicle which would otherwise cause ElectroMagnetic Interference (EMI) of the signals.
To determine whether the vehicle is CANbus or not, one way to identify is physical inspection of the vehicle Data Link Connector (DLC). For most non-CANbus vehicle, the DLC layout is shown as:
Following the pin definition according to SAE J1962, there are metal clips located on Pin #2,4,5,7, 10 and 16 and rest of the pins are not used. Also notice that Pin #6 and #14 are not used. Now, look at the other example as shown (2007 Scion tC):
Note that there are metal clips located on Pin #6 and #14 which typically indicate that the data network is equipped with CAN system. Another tip: Even though the vehicle may be equipped with CAN bus, not all control modules inside the vehicle use the same data network. For example, we find out 2007 Scion xC actually use CANbus for their Powertrain communication but ABS and Air Bag control modules still use the conventional serial 2 data bus communication. Therefore, when selecting the option on the menu, choose "CANbus" to communicate with Engine control module while "Non-CAN" to communicate with ABS and Air Bag control modules respectively.
Please comment or feel free to suggest another way to identify CAN vehicle.