Question about Ford F-150

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Ok I'm about as lost as can be. I have a 98 Ford f150 4.6 Vin 6 it is throwing a code for p0401. I have read everything possible to learn and fix it but no luck. I have changed out the egr valve. I have also changed out the dpfe. I have cleaned the egr tube as best as I can. But the check engine light still comes back on. What else is there to do? Maybe a leak somewhere? Or maybe a bad egr vacuum solenoid? I have suction on the tube going to the egr valve top. What should I do now? I need help cause state inspection is coming up real soon.

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According to a Ford truck forum, cleaning of the throttle body is a possible solution to the problem. There a couple of ports that clog.

Posted on Oct 08, 2010


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Check engine light code P0401 98 Ford expedition

OBD-II Trouble Code P0401 - Insufficient EGR Flow

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. 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.

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

Check it and keep us updated. Hope this helps (remember to rating this free answer).

Oct 13, 2011 | 1998 Ford Expedition

1 Answer

Hw do u know wat to do wen the code p0401 pop up

Hi there,

Well done on obtainging this code.

Code P0401 = Insufficient EGR circuit Flow

The EGR circuit consists of i) EGR Valve; ii) actuator solenoid; iii) differential pressure sensor. These components work together to deliver the correct amount of recirculation, depending on engine temperature, load, etc. So, when code P0401 is triggered, this means the computer has detected an insufficient amount of EGR somewhere within this circuit.

So, with this said, the possible causes are:
  • Differential Pressure (DPFE) Sensor is faulty
  • A blockage in the EGR Tube, possible caused by Carbon buildup
  • Faulty EGR Valve
  • Lack of vaccuum to the EGR valve (i.e. valve cannot open)
Note: replacing the EGR valve should only be done, after checking the other components are ok and confirming there is proper vaccuum present.

Hope this helps.....

"Please rate this solution"

Sep 04, 2011 | 1998 Ford Taurus

2 Answers

I have a code P0401. What is this and how can I fix it?

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

Mar 20, 2011 | 1998 Ford Taurus

3 Answers

Engine light is on, flashes when driving above 100 Km

stop by local parts store (Autozone,Advance, etc) and have them do a free fault code test. They can print out a list of faults and clear the codes

Jan 02, 2011 | 1998 Ford Explorer

4 Answers

I have four codes. P0136, P0141, P0171, P0401.

p0136 and p0141 are o2 sensors and p0401 is a egr flow and the p0171 means its running lean on low bank 1

Jun 30, 2010 | 1996 Ford Econoline

1 Answer

Ford 98 explorer computer malfunction

Your ECM is reading that everything is ok. The light will stay on when the problem becomes constant. You can have the codes read safely while the motor is running.

Apr 27, 2010 | 1998 Ford Explorer

2 Answers

98 windstar p0401 error code

Best explanation...

Jan 20, 2010 | 1998 Ford Windstar

1 Answer

Code P0401

Probably your EGR valve but check out this link with steps and procedures:

Jun 11, 2009 | 1998 Ford F150 Regular Cab

2 Answers

MERCURY 2000 ODB2 CODES P0400, P00A0, P0401

P00A0 is a factory readable only code (i.e. only ford dealers have the computer to read it)
the P0400 is a generic E.G.R. flow restriction code. so yes a dvom (multimeter) and a vacuum pump to diagnose it correctly, also check for loose wires as ford harness connectors are known to fail alot due to crappy phenolic content in the plastic and heat combined they can warp and / or corrode the contacts

Sep 19, 2008 | 2000 Mercury Sable

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