Engine Control System

Before connecting or disconnecting any harness connector for ECM:

Courtesy of NISSAN NORTH AMERICA, INC.

Turn ignition switch to "OFF" position.

Disconnect negative battery terminal.

Otherwise, there may be damage to ECM.
Before disconnecting pressurized fuel line from fuel pump to injectors, be sure to release fuel pressure.
Be careful not to jar components such as ECM and mass air flow sensor.