DTC Confirmation Test (Overall Function Check)

WARNING: This page is about a different car, the 2002 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the following test to check overall function of Vehicle Speed Sensor (VSS) circuit. During this test, DTC may not be confirmed.

Malfunction is detected when zero MPH signal is sent to ECM while vehicle is moving. Possible causes are:

VSS circuit open or shorted.
Defective VSS.

To check overall function of VSS circuit, raise drive wheels, and support vehicle. Using scan tool, monitor vehicle speed signal while rotating drive wheel with gear selector in suitable position. VSS signal should be able to exceed 6 MPH. If VSS signal can not exceed 6 MPH, perform DIAGNOSTIC PROCEDURE .