Technician Handbook ! 673 Electronic & Computer Controlled Systems Scope Pattern Multiplex communication signals are prime examples of signals that do not have a repeating pattern. The timing and width of the voltage pulses vary depending on the content of the messages the ECUs are trying to send over the network. Compare the signal to a conversation between people. In natural speech, you wouldn’t expect to see the same sentence repeated at a regular frequency. Comparison For that reason, when comparing scope patterns to specifications in the Repair Manual, the comparisons are not likely to be exactly the same.
In the case of the CAN low signal, the key observation is that the voltage varies between 1.5V and 2.5V and that the pulses indicating active communication are visible. Technical Training 41