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Description & Operation

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Vehicle is equipped with Supplemental Inflatable Restraint (SIR) system. When servicing vehicle, use care to avoid accidental air bag deployment. SIR system-related components are located in various locations throughout interior of vehicle, depending on application. DO NOT use electrical test equipment on or near these circuits. If necessary, deactivate SIR system before servicing components. See AIR BAG SAFETY PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in AIR BAG - Sentra RESTRAINT SYSTEMS article.
CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

Controller Area Network (CAN) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN "H" line and CAN "L" line) allowing a high rate of information transmission with less wiring. See Fig 1 . Each control unit transmits/receives data but selectively reads required data only. See Fig 2 .

Fig 1: Identifying CAN "H" & CAN "L" Communication Lines
G00227754Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Identifying Inputs & Outputs
G00227755Courtesy of NISSAN MOTOR CO., U.S.A.