Error State Indicator

A bit called Error State Indicator (ESI) follows the Bit Rate Switch (BSR). It is dominant, if the ECU is in the Error Active state. If it is recessive it indicates that the ECU is in the state Error Passive.

The purpose of this bit is to enable a more transparent way of tracking errors, as well as a simpler network management. The states Error Active and Error Passive of the network nodes are communicated on the entire network.