Powertrain Controls - ECM/PCM

Diagnostic Chart.:

Vehicle Speed Sensor Wiring.:

DESCRIPTION

Vehicle speed values are provided by the vehicle speed sensor (VSS). The sensor is a permanent magnet variable reluctance sensor (VRS) mounted on the differential area of the transaxle converter housing. The PM generator produces a pulsing voltage whenever vehicle speed is above 5 KPH (3 MPH). These pulses occur 16 times per each revolution of the differential housing and are translated to provide vehicle speed in miles per hour.

CODE PARAMETERS

Code 24 will set if:

^ The VSS indication is less than 1.6 KPH (1 MPH).

^ The engine speed is above idle.

^ The MAP indication is less than 0.5 V.

^ Vehicle not in park/neutral

DIAGNOSTIC AIDS

^ When attempting to diagnose an intermittent problem, use the Scan Tool to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem. Select MALF History from Scan Tool EC menu.

^ Check the tightness of the female terminal grip with a spare male terminal.

^ The speedometer will not work if the VSS subsystem has failed.

^ If VSS reading is accurate and speedometer is incorrect, diagnose the Instrument Cluster.

^ VSS resistance 700 - 900 ohms.

^ If problem is intermittent wiggle wires while monitoring VSS signal on scan tool and watch for signal to jump or for loss of signal.