Common EGR problem with many Fords is a bad DPFE (differential pressure) sensor. The DPFE sensor is part of the EGR system and senses EGR flow when the EGR valve is open.
It provides a feedback signal to the engine computer so it can vary EGR flow to meet changing engine loads. The DPFE sensor is usually mounted on the engine and is connected to the pipe that runs from the exhaust manifold to the EGR valve with two rubber hoses.
When the sensor goes bad, the Check Engine light comes on and typically sets any or all of teh following fault codes: P0171 & P0174 (lean codes), and/or P0401 (insufficient EGR flow). Nine out of ten times, the fault is not a bad EGR valve or a vacuum leak, but a bad DPFE sensor. A replacement costs about $112 at Ford, or about $48 at an aftermarket auto parts store
Tuesday, October 23rd, 2007 AT 3:19 PM
