If the following tests indicate that a sensor is good, and not the cause of a driveability problem or DTC, check the wiring harness and connectors between the sensor and the PCM for an open or short circuit. If no problems are found, have the vehicle checked by a dealer service department or other qualified repair shop. The vehicle speed sensor (VSS) is pickup coil (variable-reluctance) sensor mounted on the transmission. On 2000 and later models the VSS is combined with the rear axle sensor located on top of the differential. It produces an AC voltage sine wave, the frequency of which is proportional to vehicle speed. The PCM uses the sensor input signal for several different engine and transmission control functions. The VSS signal also drives the speedometer on the instrument panel. A defective VSS can cause various driveability and transmission problems. The Electronic Engine Control (EEC) system can detect sensor problems and set trouble codes to indicate specific faults. Disconnect the VSS connector and turn the ignition On but do not start the engine. Use a voltmeter to check for voltage between the sensor connector and ground as shown on the wiring diagrams. Approximately 1.5 volts should be present on one of the sensor wires with the key on and the engine off. Remove the VSS from the vehicle as described below. Connect a voltmeter to the VSS, set the meter on the AC scale, and check for voltage pulses as you spin the sensor drive gear. If no pulsing voltage signal is produced, replace the sensor. Raise the vehicle and support it securely on jackstands. Disconnect the electrical connector from the VSS. Remove the hold-down bolt and clamp and remove the VSS from the transaxle. Inspect the 0-ring on the sensor and replace it if damaged. If you are installing a new sensor, use a new 0-ring. Installation is the reverse of removal.
