CanBusTermination (2021-06-09 08:55:47)

CAN-bus must have 120 Ohm resistor termination on BOTH ends of the bus to prevent "reflection noise" ruining the signal (and communications).

This means that DVM measures 60 Ohm

This procedure must always be followed:

In general just measure across CAN+/- with DVM (ignition off)


If termination is OK (60 Ohm), watch aim2can moduls LED;


Before ordering

If you measure 60 Ohm between CAN+ and CAN-, please

  • write "please ship module with infinite Ohm termination" (solderblob open)

Without explicite information, it makes sense to ship the module with solderblob open (infinite Ohm instead of 120 Ohm termination) by default because it is always possible to install 120 Ohm resistor externally. (or closing the solderblob in the module is also easy).

Remember that these are often customized systems, and there might be other devices on the CAN-bus that may or may NOT have termination. It is always preferred to measure (needed for verification anyway), than to guess.

"To measure is to know" - Isaac Newton