2001 ford mustang service engine light on

Here is a list of possible causes. Some things you have already done.

EGR solenoid valve harness is open or shorted
- EGR solenoid valve circuit poor electrical connection
- EGR volume control valve stuck closed
- Faulty EGR Pressure sensor
- Faulty EGR temperature sensor and circuit
- Faulty EGR Valve
- EGR passage clogged
- Exhaust gas leaks
Read more: http://engine-codes.com/p0401_ford.html#ixzz28fATCih2

Are you sure you have EGR flow?? Hold the EGR valve open the engine should run poorly, if not you have no flow.

the code would run if another error before it is faulty , labors indicates ignition fault , or timing problem , I once had cogs missing on distributer ,

You need to pull the EGR valve off and check that it is free and able to open. then check the passage ways for clogging, most likely due to carbon build up.

The most likely cause of this code is a DPFE (differential pressure feedback EGR sensor).

The code 1407 indacates low or no EGR valve flow, this is normally caused by carbon build up in the passage in the intake where the valve mounts. Click over pic to see attachment...



Hope this helps.

I believe this code is insufficient EGR flow. On this engine, the passages to the EGR valve often become carboned up and cause this code. Remove the EGR valve and inspect the passages to see if they need to be cleaned.

P0104 code is MAF or VAF. This can cause surging and rough running. If you disconnect the maf and find that it runs a little better, you can be sure that a maf replacement is in order. Double check the code by erasing it then roadtest. If code comes back then it is a hard code.

It is the DPFE sensor with out this your rpms will continue surge. Alot of people make the mistake of just replacing the EGR valve instead of the DPFE sensor which measures exhaust prssure going through the EGR vavle.

dpfe sensor, also put vac to egr while car is running at idle, if car boggs down egr is working if not egr port is plugged

The DPFE (Diferential Pressure Sensor)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.I hope this helps.