This paper deploys end-to-end message checksums for error detection in the time-triggered system-on-chip architecture (TTSoCA). The end-to-end checksums are not only checked at the end, but also intermediately in the communication subsystem of the system-on-chips (SoCs) concurrently with the message transmission in order to isolate faults: if a message transmission error occurs, the goal is to pinpoint whether the fault has originated in an IP core, in the communication subsystem, or in a gateway.