P0500

Circuit Description
The Vehicle Speed Sensor (VSS) is a magnetic induction sensor. The VSS is mounted close to the output shaft gear in the transmission. The gear teeth induce an alternating current in the sensor as the output shaft rotates. This frequency is applied to the Control Module (PCM/VCM) at the rate of 40 cycles per output shaft revolution. The Control Module calculates the vehicle speed using this AC voltage signal.

If the VSS signal is not detected at any vehicle speed for 5 seconds, this DTC will set

Conditions for Running the DTC
^ No active MAP sensor DTCs
^ The MAP is less than 20 kPa
^ The ECT is 60°C (140°F) or more
^ The engine speed is between 1400-4400 RPM
^ The throttle position is less than 3 percent

Conditions for Setting the DTC
The VCM detects a vehicle speed less than 1 mph for 5 seconds or more during decel.

Action Taken When the DTC Sets
^ The Control Module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
^ The Control Module will set the DTC and records the operating conditions at the time the diagnostic fails. The Control Module stores the failure information in the scan tools Freeze Frame and/or the Failure Records.

Conditions for Clearing the MIL/DTC
^ The Control Module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the Engine Coolant Temperature is more than 70°C (158°F) during the same ignition cycle).
^ Use the scan tool Clear Information function.

Diagnostic Aids
Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:

An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis. Symptom Related Diagnostic Procedures


Inspect the face of the Vehicle Speed Sensor for metal shavings. This could result in an intermittent DTC. Also check for the following conditions:
^ A chipped or damaged rotor
^ Incorrect alignment of the rotor to the speed sensor

Test Description
The numbers below refer to the step numbers in the diagnostic table.
2. This step tests the AC voltage output of the Vehicle Speed Sensor.
6. This step tests for an internal transmission problem.