Battery Current Sensor

WARNING: This page is about a different car, the 2006 Nissan Xterra. 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.
Turn ignition switch ON.

Fig 1: Identifying Jumper Cable Between Battery Negative Terminal And Body Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
Check voltage between ECM terminal 71 (battery current sensor signal) and ground.
Voltage: Approximately 2.5V
If NG, replace battery negative cable assembly.

Fig 2: Checking Voltage Between Terminal 71 And Ground

Courtesy of NISSAN MOTOR CO., U.S.A.