An example data bus and testing system includes a data bus, first device, and second device. The first device is configured to transmit test data on the data bus, hold the transmitted test data on the data bus using a bus-hold feature, and read back the test data from the data bus during application of the bus-hold feature. The second device is configured to determine whether a fault condition exists on the data bus based on whether the read back test data differs from the transmitted test data. A method of testing a data bus is also disclosed.