DTC P0403: - Exhaust Gas RECIRCULATION (EGR) Control Circuit

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2009 Mercury Mountaineer, 2009 Mercury Milan, 2009 Mercury Mariner, 2009 Mercury Grand Marquis, and 2009 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0403: - EXHAUST GAS RECIRCULATION (EGR) CONTROL CIRCUIT

For Vehicles With an Electric EGR (EEGR)
Description:	The EEGR system is continuously monitored to check the four EEGR motor coils, circuits, and the powertrain control module (PCM) for opens, shorts to voltage and ground. If a concern is detected, the EEGR system is disabled and additional monitoring is suspended for the remainder of the drive until the next drive cycle.
Possible Causes:	EEGR motor windings open Connector to EEGR not seated Open circuit in the harness from the PCM to the EEGR Short circuit in the EEGR motor Short circuit in the harness from the PCM to the EEGR PCM
Diagnostic Aids:
For All Others
Description:	This test checks the electrical function of the EGR vacuum regulator solenoid. The test fails when the EVR circuit voltage is either too high or too low when compared to the expected voltage range. The EGR system must be enabled for the test to be completed.
Possible Causes:	EVR circuit open EVR circuit short to voltage or ground VPWR open to EGR vacuum regulator solenoid EGR vacuum regulator solenoid PCM
Diagnostic Aids:	The EGR vacuum regulator solenoid resistance is between 26 and 40 ohms.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
Crown Victoria, E-Series, Explorer 4.0L, Explorer Sport Trac 4.0L, F-150 4.6L 2V, F-Super Duty 6.8L, Grand Marquis, Mountaineer 4.0L, Mustang 4.0L, Mustang 5.4L, Town Car	GO to Pinpoint Test HH .
Escape/Mariner, Focus, Fusion, Milan, Ranger 2.3L	GO to Pinpoint Test KD .
All others	GO to Pinpoint Test HE .