2000 Oldsmobile Silhouette Logo
Anonymous Posted on Jul 20, 2009

OBD inspection: 1 trouble code reported:P0401 EGR Flow Insufficient Detected: This is a 200 Olds silhouette. Is this an easy fix?

2 Answers

Harvey N Tawatao

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  • Oldsmobile Master 3,854 Answers
  • Posted on Jul 20, 2009
Harvey N Tawatao
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Yes and know,it all depends on your experience with tools but you can do it if your follow instructions and take your time. I'll try to help you save some money and let you know that you can fix thins your self. 
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
So we are going to remove the egr valve and clean it out with Carb cleaner, remove all the carbon build up that is binding the valve. If that doesn't not work or you thing there is too much carbon or the valve it self is still binding once it's cleaned, then just replace it. The other thing to is to replace the DPFE sensor but were just going to worry about the egr first since that is what is most common and a good cleaning will always almost fix the problem. 
There is one bolt that holds the egr tube to it and two bolts that hold it to the intake manifold take them out, unplug the electrical connector and its off.  Once the egr is off, Spray it clean with Carb cleaner and make sure that there are no moving parts are binding and re-install. If needed replace the old gasket with a new one. Good luck and hope this helps and if your not sure where the egr valve is, it's just behind the throttle body. Good luck and hope this helps, Auto Zone can also give you the step by step instructions to getting the job done and you can also buy the replacement egr valve. But start with the cleaning first. 

Vincent G

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  • Oldsmobile Master 2,363 Answers
  • Posted on Dec 19, 2009
Vincent G
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Check for

vacuum leaks on intake manifold,

the air tube between the air filter.

intake manifold vacuum hose.

===
clean throttle plate with Berryman carburator cleaner

SEE sample picture HERE
===

Also remove carbon built up behind the EGR valve and the EGR passage tube.

===

Vacuum leak WILL offset the intended 14.7 to 1 air fuel ratio.

More un-metered air (leaks) will lean out the fuel mixture.

Use small amount of Berryman carb clearer at potential air leak area will help you identify trouble spot.

At idle,just spray and listen for the RPM surge.

The in-rush of carb clearer will increase the RPM on the motor.

Record the problem spot(s) and address it later.

===

EGR carbon built up require 2+ hours to clean from start to finish.

You will need a new EGR base gasket before your start.

Locate and remove the EGR valve after the vehicle is cool down.

Carefully record the connector and vacuum line (for older vehicle) location by drawing an easily to follow diagram.

Remove the EGR valve.

Inspect the location of the carbon built-up inside the valve and the EGR passage tube.

SOAK these areas with WD-40 spary.

You will need a small screwdriver,cloth hanger and lot of newspaper and time to get this cleaning done right.

RE-SOAK the carbon and let it sit for over-night will also help.

One the last round,pass a shop vacuum of the EGR valve and the passage pipe.

Install the new EGR gasket and connectors.

Allow the vehicle to warm up outdoor to burn up any remaining WD-40.


Take it for a test drive.


Please rate my answer if it's useful to you.


Cheers,

Mustgo

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You can try doing it your self.:----
To troubleshoot these issue and solve it yourself.I suggest you to go through few help links related to
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You can deatils on the following site http://www.permoveo.ltd.uk/tabid/122/OBD-Error-Code/P0401/Diagnostics/Hyundai/Default.aspx

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Generic OBD Error Code Details for P0401 Exhaust Gas Recirculation Flow Insufficient Detected What does this mean? OBD Code P0401refers to
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. SymptomsPossible sumptoms of OBD code P0401
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. CausesPossible causes of OBD code P0401
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I would check out the EGR valve. That maybe what is causing all the misfires.
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