Remote Frame
The remote frame is used by the receiving unit to request transmission of a message from the transmitting unit. It consists of six fields (see Figure 9.10): start of frame, arbitration field, control field, CRC field, ACK field, and end of frame field. A remote frame is the same as a data frame except that it lacks a data field.
Error frames are generated and transmitted by the CAN hardware and are used to indicate when an error has occurred during transmission. An error frame consists of an error flag and an error delimiter. There are two types of error flags: active, which consists of 6 dominant bits, and passive, which consists of 6 recessive bits. The error delimiter consists of 8 recessive bits.