2001 mustang with code P0104 the scanner says that EGR flow

Hi MIKE,maybe this PDFcan help you,Diagnostic Trouble Code Table ,good luck!

insufficient egr flow usually the dpfe sensor located in the back of intake manifold or mounted
on firewall.if you follow the wires/vacuum line from the egr valve you'll see it. common problem
& fairly easy job pick up a new 1 so you no what it looks like

good luck

I wouldn't have replaced the EGR valve. I would have checked the vacuum going to it. Bad vac creates bad part.

P0401 - Exhaust Gas Recirculation Flow Insufficient Detected

Possible causes - Harness or connectors (EGR volume control valve circuit is open or shorted.)
- EGR volume control valve stuck closed
- EGR volume control solenoid valve
- Dead (Weak) battery
- EGR passage clogged
- Exhaust gas leaks Possible solution - Clean EGR Valve
- Repair EGR harness or connector
- Replaced EGR volume control solenoid valve
- Replaced EGR volume control valve

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.

When you replaced the EGR valve did you check the EGR passage to make sure it wasn't clogged. Since exhaust gasses flow through the EGR passage carbon builds up on the walls restricting flow which can eventually lead to the code p0401 Insufficient EGR flow.

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.

IT ALMOST SOUNDS LIKE YOU MAY HAVE A VACUUM LEAK SOMEWHERE. USE A LENGTH OF RUBBER HOSE AND HOLD IT UP TO YOUR EAR TO PIN-POINT THE LOCATION OF A VACUUM LEAK. HOPE THIS HELPS. LET ME KNOW PLEASE. THANK YOU IN ADVANCE FOR AN HONEST RATING AND THANKS FOR USING FIX-YA. P.S. EGR VALVE IS VACUUM ACTUATED

Insufficient EGR Flow Detected

Possible Causes:
DPFE sensor signal circuit is shorted to ground
DPFE sensor VREF circuit is open between sensor and PCM
DPFE sensor downstream hose off or plugged
DPFE sensor hoses both off, loose or damaged
DPFE sensor hoses connected wrong (reversed)
EGR orifice tube is damaged or restricted
PCM has failed
And what sets the code is…….Engine started, engine running in closed loop under steady cruise conditions, and the PCM detected the DPFE sensor input indicated insufficient EGR gas flow. Run the KOER Self-Test, and if DTC P1408 is present, the fault is currently present. This code sets in 2 Trip(s). The light will stay on until the cause is repaired. A bad EGR valve is only on possible cause.

Hope this helps,

Dave

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.