- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Code 401 is for EGR flow insufficient. There is a sensor that measures how much exhaust gas goes thru the EGR valve. The sensor could have failed, or the EGR valve may not be working. The sensor and valve would need to be tested.
P0401 - EGR Flow Insufficient Detected
The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.
EGR valve stuck closed
EGR valve leaks vacuum
EGR flow path restricted
EGRVR circuit shorted to PWR
VREF open to D.P.F. EGR sensor
D.P.F. EGR sensor downstream hose off or plugged
EGRVR circuit open to PCM
VPWR open to EGRVR solenoid
D.P.F. EGR sensor hoses both off
D.P.F. EGR sensor hoses reversed
Damaged EGR orifice tube
Damaged EGRVR solenoid
Perform KOER self-test and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittents.
not likely the PCM, engine computer. they seldom go bad.
report back findings.
What does that mean? EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.
Symptoms You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.
Causes A code P0401 most likely means one or more of the following has happened: * The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced * There is a blockage in the EGR (tube), most likely carbon buildup * The EGR valve is faulty * The EGR valve may not be opening due to a lack of vaccuum
Possible Solutions In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit. * Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open * Clean out the EGR valve and/or tubing to remove deposits * Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model) * Replace the DPFE sensor (with a good quality / OEM one) * Replace the EGR valve
Hope this helped (remember comment and rated this).
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)
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
I too replaced the egr valve and was discouraged that the check engine light came back on with the same "insufficient flow" code. I took it to my mechanic to put it on the monster diagnostic machine. It said "check all vacuum line, and or map sensor". After looking real close we found a melted vacuum tube, and a cracked vacuum angle connector. Replaced both vacuum pieces, reset the codes, and good to go. If that fails than the next thing is the map sensor, that tells the EGR valve what to do.
Insufficient EGRFlow 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
Have it checked again and see what code it is. if it is P0401 it is probably the sensor shown below,
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.
You probably pulled a code p0401, insufficient egr flow. Your DPFE sensor is more than likely at fault. There has been a lot of trouble with these sensors. Then reset CEL or disconnect battery for 5 minutes.