Experiment on voltage levels

The bus lines each carry one direct-current voltage for the power supply to the connected transceiver. This voltage is called voltage level

In the following experiment you will determine the voltage level from CAN-H or CAN-L with a multimeter. Measure the voltage level against ground by touching the red probe on the uninsulated end of each of the two bus wires one after the other.

 

Versuchsergebnis The voltage level on CAN-H is volts. The voltage level on CAN-L is volts.

 

If this voltage level does not exist there is a defect in the bus. Sometimes an incorrect voltage level helps draw conclusions about the cause of failure. Diagnostic devices evaluate this level and in this manner can determine if for example there is a short in the on-board power supply. (In this case a voltage level of 12 volts would exist on the corresponding line).