Ford
Type:
    Powertrain - Transmission - ISO/SAE Controlled
Description:
    Reverse Switch Circuit Conditions
Cause:
    Engine running and PCM detected that the reverse switch signal did not change when the vehicle was shifted into or out of reverse position (switch status high instead of low)

Generic
Type:
    Powertrain - Transmission - ISO/SAE Controlled
Description:
    Reverse Input Circuit