Possible Causes

The value of the signal measured by the powertrain control module is not plausible given the operating conditions
Other low pressure EGR related DTCs
Low pressure EGR system blockage
Low pressure EGR valve mechanical integrity
Low pressure EGR differential pressure sensor signal circuit short circuit to ground, short circuit to power, open circuit, high resistance
Connector is disconnected, connector pin is backed out, connector pin corrosion
Low pressure EGR differential pressure sensor failure