For 1990-2009 cars

### Circuit 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 housing. The PM generator produces a pulsing voltage whenever the vehicle speed is above 5 km/h (3 mph). These pulses occur 16 times per each revolution of the differential housing and are translated to provide the vehicle speed in miles per hour.

### Conditions for Setting the DTC

DTC P0500 will set if there is no VSS signal when:

• | The engine speed is between 1400-4000 RPM. The MAP sensor indication is less than 0.5 volts, less than 23 kPa (3 psi) for greater than 5 seconds.

• | The vehicle is not in park/neutral, with an automatic transaxle.

Important: The VSS signal is continuously checked once the above conditions are met. If the VSS signal is missing the speedometer will be inoperative.

### Diagnostic Aids

When attempting to diagnose an intermittent problem, use the scan tool to review the malfunction history diagnostic information. The supplemental data can be used to duplicate a problem.

Intermittents or opens suspected to be at the connector can be detected by using a diagnostic service probe. Voltage can be read on wires without disconnecting any connectors.

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 the VSS reading is accurate and the speedometer is incorrect, refer to Audio Systems and I/P Cluster service manual.

• | The VSS resistance = 800-1600 ohms.

• | If the problem is intermittent, wiggle the wires while monitoring the VSS signal on the scan tool and watch for the signal to jump for loss of signal.

• | The PCM will calculate the VSS based on RPM and TP sensor signal if DTC P0500 is set, but the speedometer will remain inoperative.