DTC Confirmation Test (Overall Function Check)

Malfunction is detected when zero MPH signal is sent to ECM while vehicle is moving. Depending on equipment available, use one of the following to check function of VSS circuit:

• Using Scan Tool
  
  Raise drive wheels and support vehicle. Start engine. With transmission in a forward gear and wheels turning at 6 MPH, select MODE 1 and check VSS output signal. VSS output signal should be 6 MPH.
• Using MIL
  
  Raise drive wheels and support vehicle. Connect an oscilloscope between ground and ECM harness connector terminal No. 29 by backprobing. See Figure. Start engine. Shift transmission into a forward gear. Increase engine RPM until drive wheels are rotating at 25 MPH. VSS signal should be as shown. See Fig 1.

Fig 1: Checking VSS Signal At ECM

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