Battery Current Sensor

WARNING: This page is about a different car, the 2007 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

Reconnect harness connectors disconnected.
Disconnect battery negative cable.
Install jumper cable between battery negative terminal and body ground.

Fig 1: Identifying Jumper Cable Between Battery Negative Terminal And Body Ground
Courtesy of NISSAN NORTH AMERICA, INC.
Turn ignition switch ON.
Check voltage between ECM terminal 71 (battery current sensor signal) and ground.
Voltage: Approximately 2.5V

Fig 2: Checking Voltage Between ECM Terminal 71 (Battery Current Sensor Signal) And Ground
Courtesy of NISSAN NORTH AMERICA, INC.
If NG, replace battery negative cable assembly.