EGR SYSTEM PROBLEM

I have copied the entire description for the code.
Let me know if you need more info. You may need a shop to take a look at the system.

P1405 Ford Description
The purpose of the Exhaust Gas Recirculation (EGR) system on your engine is to limit oxides of nitrogen (NOx) emissions. This is done by redirecting small amounts of exhaust gas back through the upper intake to get mixed in with the air/fuel charge. The resultant diluted air/fuel mixture (i.e., less oxygen per cubic foot) burns cooler and combustion chamber temperatures are reduced accordingly, thereby lowering NOx emissions.
The Ford DPFE/EGR system is controlled by the Powertrain Control Module (PCM). The system employs an EGR Valve, an Electronic Vacuum Regulator (EVR), and a Delta Pressure Feedback EGR sensor (DPFE).
The DPFE Sensor measures EGR flow across an orifice located inside the special EGR Tube. The orifice is positioned between two hose ports coming off the tube which are connected to the DPFE sensor with special heat-resistant hoses. When the EGR Valve is open, a pressure differential is created across the orifice (intake manifold pressure vs. exhaust pressure). By design, this difference in pressure is measured by the DPFE sensor in terms of voltage. The DPFE voltage signal output to the PCM is directly proportional to the flow of exhaust gas entering the intake manifold.

Read more: http://engine-codes.com/p1405_ford.html#ixzz2dUIwIiDd

sounds like a job for a Chilton's guide..

You can have a look at the position of EGR valve and where it is located in following link:

This is the DPFE(Delta Pressure Feedback) sensor. Some places may call it an EGR(Exhuast Gas Recirculation) sensor but that's not really what it is.

1996 Ford Explorer 2WD 5.0L

Canister Purge Valve
Catalytic Converter

EGR Position Sensor

EGR Vacuum Solenoid

EGR Valve

EGR Valve Gasket

EGR Valve Pressure Sensor

Exhaust Manifold

Exhaust Manifold Gasket

Fuel Cap

Muffler - Performance

Oxygen Sensor

PCV Valve

Sensor - Ambient Air Temperature

Smog Pump

This sensor delta pressure feedback sensor for the egr is located on the top right side of the intake manifold, heres a diagram that will also help in locating this sensor, hope this is helpful.

Dpfe sensor is usually on driver side intake manifold or on a bracket attached to it. It has 2 vacuum ports & a electrical plug. Look for cracked or broken vauum hoses going to it. I would fix any broken vacuum hoses, if none change the dpfe sensor(aka:egr position sensor) only & it will usually cure both codes.

PO401 code means that:
The PCM has determined that there is insufficient flow in the exhaust gas recirculation system. Definition: EGR system fault (Exhaust Gas Recirculation) Probable Causes: a. Blocked passage on EGR system b. Failed EGR Valve c. EGR solenoid faulty d. Failed EGR pressure sensor where applicable e. Failed EGR position sensor where applicable

they come off the exhaust manifold...

The egr valve has two sensors. One is an EGR position sensor which is physically attached to the EGR valve. The other sensor is the DPFE (Delta Pressure Feedback EGR) sensor, commonly called the EGR pressure sensor. It's location varies depending on the engine you have. You can fine this sensor by following the vacuum hose on the EGR valve. It will be with in inches of the EGR valve. The sensor will be black (plastic) or silver (metal), have two or three vacuum ports and an electrical connection on it.

The vacuum pressure sensor is a high failure item on fords. Any Ford parts department will have one in stock, as well as some aftermarket parts stores.

The new sensor may not look exactly the same as the old part, but will have all the hook ups as the old one. You may also need to replace the vacuum hose to the sensor as well