With Manual Transmission

DTC P0502












Circuit Description
The Vehicle Speed Sensor (VSS) assembly provides vehicle speed information to the Powertrain Control Module (PCM). The VSS assembly is a permanent magnet generator. The VSS produces Alternating Current (AC) as the rotor teeth on the output shaft of the transmission pass through the sensor's magnetic field. The frequency and amplitude of the AC waveform both increase as vehicle speed increases.
If the PCM detects no vehicle speed for a specified length of time while other sensors indicate that the vehicle is moving, DTC P0500 sets. DTC P0500 is a type A DTC.

Conditions for Running the DTC
^ DTCs P0107, P0108, P0122, and P0123 are not set.
^ The engine speed is 1700- 3600 RPM.
^ The Throttle Position (TP) is 0-1 percent.
^ The engine vacuum is 80-70 kPa.
^ The above conditions are met for 5 seconds.

Conditions for Setting the DTC
The vehicle speed is less than 3 km/h (2 mph).

Action Taken When the DTC Sets
^ The Malfunction Indicator Lamp (MIL) illuminates.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
^ Cruise Control is disabled.
^ The coolant fan turns ON.
^ The PCM stores DTC P0502 in PCM history.

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL during the third consecutive trip in, which the diagnostic test runs and passes.
^ The PCM cancels the DTC default actions when the fault no longer exists and the DTC runs and passes.
^ A history DTC will clear after 40 consecutive warm-up cycles without a fault.
^ A scan tool can clear the MIL/DTC.

Diagnostic Aids
Ensure the VSS is correctly torqued to the transmission housing.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
5. The resistance measurement will not change if either the VSS high signal circuit or the VSS low signal circuit (but not both) is shorted to ground. The vehicle speed detector in the PCM and the VSS are matched in such a way that an open or a short to ground in the VSS low signal circuit will not usually cause a loss of speed signal or a DTC P0502 to set.
8. This step isolates the short between the VSS and the wiring.
10. Do not skip Step 7. The DMM will detect AC voltage if the VSS high signal circuit is shorted to ground.
13. The replacement PCM must be programmed and the crankshaft position system variation procedure must be performed.