P0500

DTC P0500 Vehicle Speed Sensor (VSS) Circuit






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 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 diagnostic trouble code (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) the first time the diagnostic runs and fails.
- 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/Failure Records.

Conditions for Clearing the MIL or 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. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
- Use a scan tool in order to clear the DTCs.

Diagnostic Aids

Thoroughly check any circuitry that is suspected of causing the intermittent complaint.

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.

Test Description

The numbers below refer to the step numbers in the diagnostic table.

2. This test checks the AC voltage output of the vehicle speed sensor.
6. This test checks for an internal transmission problem.