P0406 - Exhaust Gas RECIRCULATION (EGR) Sensor A Circuit High

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2008 Mercury Sable, 2008 Mercury Mountaineer, 2008 Mercury Milan, 2008 Mercury Mariner, and 2008 Mercury Grand Marquis. However, it is still accessible from the selected car via links, so may be relevant.

P0406 - EXHAUST GAS RECIRCULATION (EGR) SENSOR A CIRCUIT HIGH

Description:	The EGR monitor checks the EGR sensor signal to the powertrain control module (PCM) for high voltage. The test fails when the average voltage to the PCM exceeds the maximum calibrated value.
Possible Causes:	Differential pressure feedback EGR circuit open VREF circuit short to voltage Damaged differential pressure feedback EGR sensor Differential pressure feedback EGR circuit short to voltage SIG RTN circuit open
Diagnostic Aids:	A DPFEGR PID reading greater than 4.5 volts with the key ON, engine OFF or running indicates a hard fault.
Application		Key On Engine Off	Key On Engine Running	Continuous Memory
Vehicles with an EGR system module (ESM)		refer to PINPOINT TEST HH .
All others		refer to PINPOINT TEST HE .