The contribution of this paper is threefold. First, an improvement to a previously published paper on the timing analysis of Controller Area Network (CAN) in the presence of transient network faults is presented. A probabilistic fault model is considered, where random faults from electromagnetic interference occur according to a Poisson distribution. The analysis provides worst case response times for message frames, not as a single value, but as a probability distribution. Secondly, a similar result is produced for timetriggered CAN (TTCAN), a version of CAN based on timedriven schedule. Thirdly, these analyses are applied to an example message set and used to discuss the dependability of event-triggered and time-triggered communication in the presence of electromagnetic interference. The results indicate that, an event-triggered bus can generally provide a higher probability of timely-delivery of data than a timetriggered bus.