Diagnostic Aids

Check all connections, especially at transmission pass-thru connector. If the input sensor is not operational at start up, it can cause the VSS to read zero. While Code 24 is set, scan tester will display RPM derived from input speed.

Fig 1: Schematic, Vehicle Speed Sensor ("C" & "K" Series)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Schematic, Vehicle Speed Sensor ("G" Series)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Schematic, Vehicle Speed Sensor ("P" Series)

Courtesy of GENERAL MOTORS CORP.

Fig 4: Flowchart, Vehicle Speed Sensor

Courtesy of GENERAL MOTORS CORP.