With Automatic Transmission

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Vehicle Speed Sensor (VSS) provides the vehicle speed information to the Powertrain Control Module (PCM). The VSS is a signal generator that produces an AC voltage. The VSS is mounted in the transaxle. The AC voltage range and the number of pulses per time period increase with the vehicle's speed.

CONDITIONS FOR RUNNING THE DTC
The vehicle is operating in the fuel cutoff mode.

CONDITIONS FOR SETTING THE DTC
^ There is not any vehicle speed sensor signal.
^ The condition is present for more than 4 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active.
^ The PCM records the operating conditions at the time that the diagnostic fails. The Freeze Frame buffer stores this information.
^ The PCM enters the Fail-Safe Function and stops idle speed feedback control.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The MIL turns OFF after three consecutive trips, during which the diagnostic runs and there are not any faults that are detected.
^ A History DTC clears after 40 consecutive warm-up cycles without a fault.
^ Use the Clear DTC Information function on the scan tool, or disconnect the PCM battery feed in order to clear the DTC.

DIAGNOSTIC AIDS
A fault in the VSS electrical circuit may cause an intermittent malfunction. Inspect the wiring harness and the components for any of the following conditions:
^ Backed out terminals
^ Incorrect mating of terminals
^ Broken electrical connector locks
^ Incorrectly formed terminals or damaged terminals
^ Faulty terminal-to-wire connections
^ Physical damage to the wiring harness
^ A broken wire inside the insulation
^ Corrosion of electrical connections, of splices or of terminals

If a DTC P0500 cannot be duplicated, the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was set.

TEST DESCRIPTION
The numbers below refer to the step numbers in the diagnostic table.
1. The Powertrain OBD System Check prompts the technician to complete some basic checks, and to save the applicable freeze frame data on the scan tool. This creates an electronic copy of the data that was taken when the fault occurred. The scan tool saves the information for later reference.
2. This step determines if the fault is present.
4. This step checks the resistance of the VSS.