taking your vehicle to a qualified reair shop to have it diagnosed would be a good thing to do . You could not have traced all wires ! Because i'm sure you haven't any idea how this works . An a factory scan tool is a must to diagnose this .Do you know what ford SCP data network is ?
The instrument cluster receives the vehicle speed signal from the powertrain control module (PCM) over the standard corporate protocol (SCP) network and displays it on the speedometer gauge. If the instrument cluster receives no vehicle speed signal after one second, the speedometer defaults to 0.0 km/h (0.0 mph).
Vehicle Speed Sensor
The vehicle speed sensor (VSS) (Figure 52) is a variable reluctance or Hall-effect sensor that generates a waveform with a frequency that is proportional to the speed of the vehicle. If the vehicle is moving at a relatively low velocity, the sensor produces a signal with a low frequency. As the vehicle velocity increases, the sensor generates a signal with a higher frequency. The PCM uses the frequency signal generated by the VSS (and other inputs) to control such parameters as fuel injection, ignition control, transmission/transaxle shift scheduling and torque converter clutch scheduling.
P0500 - Vehicle Speed Sensor (VSS) Malfunction
Indicates the powertrain control module (PCM) detected an error in the vehicle speed information. Vehicle speed data is received from either the vehicle speed sensor (VSS), the transfer case speed sensor (TCSS) or the anti-lock brake system (ABS) control module. If the engine RPM is above the torque converter stall speed (automatic transmission) and the engine load is high, it can be inferred that the vehicle must be moving. If there is insufficient vehicle speed data input, a malfunction is indicated and a DTC is set. On most vehicle applications the malfunction indicator lamp (MIL) is triggered when this DTC is set.
- Open in the VSS+/VSS- harness circuit.
- Open in the TCSS signal or the TCSS signal return harness circuit.
- Short to GND in the VSS harness circuit.
- Short to GND in the TCSS harness circuit.
- Short to PWR in the VSS harness circuit.
- Short to PWR in the TCSS harness circuit.
- Damaged drive mechanism for VSS or TCSS.
- Damaged VSS or TCSS.
- Damaged wheel speed sensors.
- Damaged wheel speed sensor harness circuits.
- Damage in the module(s) connected to the VSC/VSS circuit.
- Open or short in the vehicle speed circuit VSS signal between the ABS VSS signal output and the VSS signal inputs to the PCM and other modules (Excursion and F-Super Duty).
Monitor the VSS PID while driving vehicle. This DTC is set when the PCM detects a sudden loss of vehicle speed signal over a period of time. If vehicle speed data is lost, check the source of where the vehicle speed input originates from: VSS, TCSS or ABS. Note: On some MSOF applications, VSS and TCSS PID can be monitor. However if no TCSS PID is available and VSS PID is zero, TCSS circuitry frequency must be checked for loss of sensor signal. If another vehicle electronic module has generated the P0500 and the vehicle does not receive its vehicle speed input from one of the above mention sources (VSS, TCSS or ABS). Check the PCM for Output Shaft Speed Sensor (OSS) DTCs. On OSS applications the PCM uses the OSS to calculated the vehicle speed. If no OSS DTCs are found check for correct PCM configuration. Check PCM configuration for correct tire size and axle ratio.
P0501 - Vehicle Speed Sensor (VSS) Range/Performance
Indicates the powertrain control module (PCM) detected an error in the vehicle speed information. This DTC is set the same way as P0500, however the malfunction indicator lamp (MIL) is not triggered.
- Refer to possible causes for P0500.
Refer to Diagnostic Aids for P0500.
P0503 - Vehicle Speed Sensor (VSS) Intermittent
Indicates poor or noisy VSS performance. Vehicle speed data is received from either the vehicle speed sensor (VSS), the transfer case speed sensor (TCSS), or the anti-lock brake system (ABS) control module.
- Noisy VSS/TCSS input signal from the radio frequency interference / electro-magnetic interference (RFI/EMI) external sources, such as ignition components or the charging circuit.
- Damaged VSS or driven gears.
- Damaged TCSS.
- Damaged wiring harness or connectors.
- Malfunction in the module(s) or circuit connected to the VSS/TCSS circuit.
- After market add-on.
Monitor the VSS PID while driving the vehicle. Check for intermittent vehicle speed indication. Verify the ignition and charging system are functioning correctly.