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P0401 Exhaust Gas Recirculation Flow Insufficient Detected

Clogged passage or bad valve

Posted on Aug 10, 2017


6 Suggested Answers

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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
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Posted on Jan 02, 2017

  • 67 Answers

SOURCE: Emission test found some trouble codes

U0121 Communication error to ABS HU/CM

Posted on Apr 06, 2009

  • 65 Answers

SOURCE: My 1991 4runner failed emissions test with high CO and HC levels.

Not sure, but did you replace the oxygen sensors. Is your catalytic converter still good?

Posted on Aug 21, 2009

  • 3854 Answers

SOURCE: Did not pass state inspection (vehicle)

First the fault codes,
U110C is No Fuel Level Bus Message
U0155 is No Cluster Bus Message.
Unfortunatly you have to be able to communicate with the instrument cluster with your scanner to diagnoise and I do not think an aftermarket scanner can do this.

Posted on Mar 02, 2010

  • 22306 Answers

SOURCE: My emission test fail with the mil cmd fail code

the code reader couldnt access the software so its a dealer only job ,we do not have this probelm in europe as a sensor probe is inserted into the exhaust pipe ,Only the dealer can access the diadnosis socket here in europe and new cars have to be accessed via the internet as not even the dealers have the software ,its to stop the chinese from hacking and selling the software over the internet so the ECU has a encryption chip that changes the codes used 3 times a second just like satalite TV card

Posted on Apr 24, 2011

  • 4803 Answers

SOURCE: Have 1999 Mercury Sable and failed emissions for P0401 code, I replaced the EGR Valve and had the code reset, service engine light came on again Approx 15 miles later. Took it to Auto Zone and they g

I am not surprized. The chances that replacing an EGR valve will fix a code P0401 on ANY Ford vehicle is about 1/2 of 1 percent. You most likely either have clogged up EGR ports in your intake manifold, or you have a defective Delta Pressure Feedback EGR (DPFE) sensor.

To find out which it is, apply vacuum to the EGR valve vacuum port with the engine idling. The engine should stumble and/or stall. If it does not, your ports are clogged. If it does, the most likely cause of your problem is the DPFE sensor. However, the EGR vacuum control solenoid could also be the cause.
You cannot properly test the EGR vacuum control solenoid without the proper equipment, but you can check to make sure that there is manifold vacuum going into one side of the solenoid and you can check to make sure that there are no breaks or leaks in the line that runs between the solenoid and the valve. If you find any of these, repair as necessary. If you do not find a problem with the vacuum lines, then you can take a "guess" and replace the DPFE. If this does not work, then you can "guess" again and replace the solenoid. If it still does nort work, then you probably have a bad electrical circuit to the solenoid (once again, requiring the proper equipment to diagnose).

Please also review the following article: What Else Could Be Wrong?

Posted on Nov 26, 2011

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2 Answers

How do I correct a P0401 code on my 2.2 chevy corsica

The passages are plugged ! pull EGR valve an inspect passages and the pipe for a restriction or damage and repair as necessary.

May 30, 2015 | Chevrolet Corsica Cars & Trucks

1 Answer

P1443,p0401 and po420 failed emission

P1443 is an EVAP code which means the purge control solenoid.P0401 is an EGR valve and code p0420 is a catalytic converter.

Mar 28, 2014 | Cars & Trucks

1 Answer

P1443,po420 and po401 -failed emission... how to repair

p1443 is Purge control solenoid , p0420 is catalytic converter and Egr vale for code p0401

Mar 28, 2014 | Cars & Trucks

1 Answer

My engine light is on so i took an OBD reading and it showed the error codes P0401, P0420 and P0133. What do I need to fix?

P0401 is EGR valve, low circulation detected.
P0420 Catalyst system.
P0133 is O2 sensor bank 1 sensor 1.
All these codes are emissions related, so i would start with the EGR valve, it's probably clogged with carbon. The catalytic converter could be also, check that for excessive backpressure. The oxygen sensor can be tested, replace if needed. Good luck, i hope this helps.

Jul 29, 2011 | 2000 Honda Prelude

1 Answer

The check engine light is on, the EGR valve has been replaced, code P0401 appears on diagnostic. The engine is 4 cyl DOHC 2 wd. slight exhaust odor at times in vehicle.

Are you reset the stored codes there? The EGR (Exhaust Gas Recirculation) valve controls an engine's emission of smog-causing nitrous oxides, or NOx. Its job is to route a portion of the exhaust gases back into the intake manifold. That lowers combustion temperature to below 2,500 degrees Fahrenheit - the temperature at which NOx gases form.

EGR flow is controlled by the engine's computer, which opens or closes the valve as needed. The EGR system is, for the most part, in the "out of sight, out of mind" category, and typical doesn't require regular maintenance. But if it gets clogged with carbon deposits, you'll see your "check engine" light come on, and a code (perhaps P0401 or P0402 or P0403) will show that there is insufficient flow. That typically results from a vehicle being driven persistently on short trips that don't allow the engine to fully warm up. Flow problems also can be caused by carbon buildup due to failure to change the oil frequently enough.

A clogged EGR valve not only results in higher emissions, it can affect fuel economy and cause rough idling - even serious engine damage. Valves can usually be cleaned, but replacement is often recommended.

About thie generic fault code, I suggtes check this description and tips for solution information: DTC-P0401-Tests (keep in midn that this code applied for alot brands, Hyundai included).

Keep us updated.

Feb 09, 2011 | 2003 Hyundai Santa Fe

1 Answer

My Ford Taurus just failed a vehicle emission test due to diagnostic codes P0401, P0402, and P1400. Can you tell me what these codes are for and what type of repair is needed? Thanks.

plz check the fuel and carborater first then go for silencer (if your car runned above 15000 kms got repair shop) even u can neglet, coz thees error come during winter sesion [they are related to carben and moister]

Jun 23, 2010 | 2002 Ford Taurus

1 Answer

Need to know how to change the gr valve. Can;t locate it.

As your engine wears, horrible black grunge builds up in the EGR and closes it off like an artery. The net result is .. you fail the emissions tests There are frour related items on any Ford truck to your EGR system. You must know what item is bad. The valve can be checked easily by removing it and check if it holds vacuum. Also clean the internal area with carbon build up. The solenoid, relay switch, & manifold switch can not be restored at all

May 24, 2009 | 1998 Ford F150 Regular Cab

1 Answer

1997 Toyota Celica Failed Emissions Testing

Generaly o2 code comes up when anything at all is wrong in the combustion process. I'd have the egr valve tested and cleaned as well as the passages to and from it...They often get plugged up with carbon.

Apr 09, 2009 | 1997 Toyota Celica

1 Answer

1997 Toyota Celica - Codes P0133 & P0401

well if its poping an o2 code try a couple things before you start spending money. when it starts up listen for a rattle from the cattilitic convertor. if you have a bad rattle replace the cat that might solve both codes if no rattle replace the o2 sensor, it might just be that. hope this helps

Apr 09, 2009 | 1999 Saturn SL

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