Ford
Type:
    Powertrain - Transmission - ISO/SAE Controlled
Description:
    Incorrect Gear Ratio Conditions
Cause:
    Engine running in first gear with VSS signals received, then the PCM detected an incorrect gear ratio

Generic
Type:
    Powertrain - Transmission - ISO/SAE Controlled
Description:
    Input/Turbine Speed Sensor "A" Circuit No Signal

GM
Type:
    Powertrain - Transmission - ISO/SAE Controlled
Description:
    Input Speed Sensor Circuit Low Input (4T80-E Transmission)
Cause:
    DTC P0502, P0503m P1820, P1822, P1823 and P1825 not set, system voltage from 8-18v, engine runtime over 5 seconds, Fuel Cutoff inactive, Transmission not in Park or Neutral, VSS over 10 mph, then the PCM detected that the Input Speed was less than 51 rpm, conditions met for six seconds