How to test your DPFE sensor.
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Joined: Nov 2009
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DPFE Sensor
My 95 ford explorer check engine light came on, I ran the codes and got code 327, which says EGR Valve Transducer/position sensor circuit below minumum voltage, I replaced the sensor and replaced the vacume hoses as well, ren codes and got code 111 which means everthing passed. No more check engine light for about 8 days then check engine light again...ran codes and got 337 this time which is sensor circuit voltage is above minimum voltage, went back to autozone got another dpfe, everythinh worked great for about 2 weeks then same thing..got code 327 again...this has went on for 4 dpfe sensors now another sensor is bad # 5..all these sensors are from auto zone not from Ford...One mechanic on line told me it has to be the dpfe...said that I need to get Factory Ford DPFE sensor and this will probably solve my problem..The auto zone sensors were all under a warranty and cost 59 bucks compared to Fords 180 buck sensor but doesn't really matter if they all are failing. I just do not want to get Factory part and pay 180 for it and have the same problem, auto zone replaced all the sensors no questions asked but I am sure Ford will not be so kind if I huy it and 2 weeks later it goes bad..Is there anything else that could cause the sensor to go bad...One thing that puzzles me is that every time I replace the sensor it solves the problem but only short term..I just thought it would be very rare to have 5 sensors go bad even if they are not from Ford..One other thing is when the engine light comes on it will stay on untill I turn the engine off, I can turn it off and right back on and it will take the light a few minuts to come back on.
I appreciate any advice and input any one can give me on this problem. As I say I don't mind going to Ford and getting the sensor if I am sure all these generic sensors went bad on their own
I appreciate any advice and input any one can give me on this problem. As I say I don't mind going to Ford and getting the sensor if I am sure all these generic sensors went bad on their own
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Joined: Nov 2009
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From: Seattle
Jody54,
I bought a '99 F-250 Super Duty, 6.8L V10 back last month (mid-Oct.) I bought it from a dealer, and after approx. 150 miles, the CEL illuminated. (I can tell that the dealer reset all codes by disconnecting the battery...it was pretty obvious.) I checked the code, and I got a P0401 (insufficient EGR flow). I spoke to a certified Ford mechanic on another site, and he told me to replace the DPFE sensor after checking the EGR valve. The EGR valve checked out (like he said...also said that these rarely fail), so I replaced the DPFE sensor with one from Autozone. Well, guess what? Two weeks and a few hundred miles later, the CEL came on, again. This time, I got a P0402 code (excessive EGR flow). I spoke to another Ford certified mechanic on the same site that I spoke to the other one, and this guy tells me to replace the DPFE sensor. I told him that I already did that. He asked where I got the replacement from, and I told him that I got it from Autozone. He told me that the problem was that I got an aftermarket sensor from Autozone....told me not to buy aftermarket sensors from parts houses but to buy those directly from Ford. Anyway, I used the test procedure that was shown at the beginning of this thread, and sure enough, the DPFE sensor is faulty...again. Suppose that I'll take the advice of the last mechanic I spoke with and get the DPFE directly from Ford. Yeh...I'll pay $165 for one from Ford compared to $65 for the one I got from Autozone, but I guess you get what you pay for. Buy cheap, you get cheap. Oh well...live and learn. Like Bill Clinton used to say, "I'll feel your pain." lol.
I bought a '99 F-250 Super Duty, 6.8L V10 back last month (mid-Oct.) I bought it from a dealer, and after approx. 150 miles, the CEL illuminated. (I can tell that the dealer reset all codes by disconnecting the battery...it was pretty obvious.) I checked the code, and I got a P0401 (insufficient EGR flow). I spoke to a certified Ford mechanic on another site, and he told me to replace the DPFE sensor after checking the EGR valve. The EGR valve checked out (like he said...also said that these rarely fail), so I replaced the DPFE sensor with one from Autozone. Well, guess what? Two weeks and a few hundred miles later, the CEL came on, again. This time, I got a P0402 code (excessive EGR flow). I spoke to another Ford certified mechanic on the same site that I spoke to the other one, and this guy tells me to replace the DPFE sensor. I told him that I already did that. He asked where I got the replacement from, and I told him that I got it from Autozone. He told me that the problem was that I got an aftermarket sensor from Autozone....told me not to buy aftermarket sensors from parts houses but to buy those directly from Ford. Anyway, I used the test procedure that was shown at the beginning of this thread, and sure enough, the DPFE sensor is faulty...again. Suppose that I'll take the advice of the last mechanic I spoke with and get the DPFE directly from Ford. Yeh...I'll pay $165 for one from Ford compared to $65 for the one I got from Autozone, but I guess you get what you pay for. Buy cheap, you get cheap. Oh well...live and learn. Like Bill Clinton used to say, "I'll feel your pain." lol.
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Joined: Aug 2006
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From: W. Wisc
Yeah it's a common failure with time on Fords...-Dave
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DPFE
MLB
I can attest to everything you said above, I have a 95 ford Explorer, 115,000 miles on, CEl came six weeks ago, first time ever..To make a long story short, I went through 5...count em FIVE DPFE sensors from autozone, only had to pay for the first one and it is a good thing they are a snap to change but point is they all lasted no more than 2 weeks and CEL on again, Bought Ford DPFE and no more problems, been a month now.
Ford wanted 185 for the part, after reading a post that said he got his on ebay I looked on Ebay, found one, brand new for 70 bucks.
Yep ... you can NOT use after market DPFE's on Fords,after 5 of them and reading and getting advice from this site, I found that out
I can attest to everything you said above, I have a 95 ford Explorer, 115,000 miles on, CEl came six weeks ago, first time ever..To make a long story short, I went through 5...count em FIVE DPFE sensors from autozone, only had to pay for the first one and it is a good thing they are a snap to change but point is they all lasted no more than 2 weeks and CEL on again, Bought Ford DPFE and no more problems, been a month now.
Ford wanted 185 for the part, after reading a post that said he got his on ebay I looked on Ebay, found one, brand new for 70 bucks.
Yep ... you can NOT use after market DPFE's on Fords,after 5 of them and reading and getting advice from this site, I found that out
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DPFE Failed
i got a P0402 code- "EGR Excessive flow detected" on my 98 Expedition, which turned out to be from defective DPFE sensor. Unfortunately, i didnt figure this out until after I had changed the EGR valve.
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Joined: May 2009
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My 2000 EB Expedition with 92K miles just came up with code: P1405. I used the OBD-2USB adapter from http://www.odbcom.com and it has been a great tool to have. I also crossed referenced the part from http://www.tomco-inc.com/Catalog/dpfe%20sensors.pdf and exactly located the illustrated part, figure 3 by unbolting the 3 bolts to the Throttle Body plastic cover and it was on the right side.
I have not noticed any poor performance in the vehicle, but again, it's a 2000 Expedition with 92K miles on it.
My question is, should I just replace the DPFE sensor and hoses all together being just because of the mileage on the vehicle?
I have not noticed any poor performance in the vehicle, but again, it's a 2000 Expedition with 92K miles on it.
My question is, should I just replace the DPFE sensor and hoses all together being just because of the mileage on the vehicle?
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There has been a lot of talk about the DPFE sensor going bad so I thought I would post a "how to" test the sensor. You will need a volt meter, safety pin and a 3 or 4 ft piece of hose (about 1/4" ID). If you know where the sensor is located skip to the next paragraph. Remove the black plastic cover (3 screws) exposing the throttle body and other fuel related things. Its the cover in the center of your engine that says something like 5.4L or 4.6L on it. Now the DPFE sensor has 2 rubber hoses (about 3/8" dia) coming off the bottom leading in to 2 metal tubes which are leading into a 1" metal EGR pipe coming off the exhaust manifold. On the side of the sensor is a 3-wire connector. This assembly is the DPFE sensor.
Remove the 2 rubber hoses from the bottom of the sensor. Attach a piece of rubber hose to the forward most hole in the sensor. Now carefully take a small safety pin and stick it in behind the top wire parallel to the wire. You do NOT want to pierce the wire, only make contact inside the connector. This top wire is the active feedback signal wire. It will vary from 0-5 volts or so. The middle wire is ground. The bottom wire is 5-6 volts supply. Now the top wire voltage will vary as the pressure between the two holes in the sensor varies. Set your meter to read volts, either turn the key until the accessories are on or start the engine, either way is fine. Now using your mouth apply suction to the hose and you will see the voltage change from near 0 to near 5 if you apply enough suction. The vacuum on the hose should hold your tongue and not leak. If the voltage does not vary or is stuck high or low, the sensor is bad. Do the same thing to the rear port but the voltage difference will be much less, this is the reference port.
If the sensor seems to be working then you can further test the system by doing the following. Attach the hoses to the sensor as normal. Now remove the rubber vacuum hose from the top of the EGR valve diaphragm. With the truck running apply slight vacuum to the EGR valve and this will open the EGR valve. When the valve opens you will see the voltage on the top wire of the DPFE sensor change indicating flow. When the vacuum is applied your truck should stumble or almost stall indicating the EGR valve has opened which it normally does not do at idle. I hope this helps.
Remove the 2 rubber hoses from the bottom of the sensor. Attach a piece of rubber hose to the forward most hole in the sensor. Now carefully take a small safety pin and stick it in behind the top wire parallel to the wire. You do NOT want to pierce the wire, only make contact inside the connector. This top wire is the active feedback signal wire. It will vary from 0-5 volts or so. The middle wire is ground. The bottom wire is 5-6 volts supply. Now the top wire voltage will vary as the pressure between the two holes in the sensor varies. Set your meter to read volts, either turn the key until the accessories are on or start the engine, either way is fine. Now using your mouth apply suction to the hose and you will see the voltage change from near 0 to near 5 if you apply enough suction. The vacuum on the hose should hold your tongue and not leak. If the voltage does not vary or is stuck high or low, the sensor is bad. Do the same thing to the rear port but the voltage difference will be much less, this is the reference port.
If the sensor seems to be working then you can further test the system by doing the following. Attach the hoses to the sensor as normal. Now remove the rubber vacuum hose from the top of the EGR valve diaphragm. With the truck running apply slight vacuum to the EGR valve and this will open the EGR valve. When the valve opens you will see the voltage on the top wire of the DPFE sensor change indicating flow. When the vacuum is applied your truck should stumble or almost stall indicating the EGR valve has opened which it normally does not do at idle. I hope this helps.
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From: St Louis
He said to use a volt meter, not an amp meter. They are different tools (or functions within the same tool)
Voltage readings are always measured relative to ground unless otherwise instructed.
Voltage readings are always measured relative to ground unless otherwise instructed.
New User
Joined: Jan 2011
Posts: 3
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There has been a lot of talk about the DPFE sensor going bad so I thought I would post a "how to" test the sensor. You will need a volt meter, safety pin and a 3 or 4 ft piece of hose (about 1/4" ID). If you know where the sensor is located skip to the next paragraph. Remove the black plastic cover (3 screws) exposing the throttle body and other fuel related things. Its the cover in the center of your engine that says something like 5.4L or 4.6L on it. Now the DPFE sensor has 2 rubber hoses (about 3/8" dia) coming off the bottom leading in to 2 metal tubes which are leading into a 1" metal EGR pipe coming off the exhaust manifold. On the side of the sensor is a 3-wire connector. This assembly is the DPFE sensor.
Remove the 2 rubber hoses from the bottom of the sensor. Attach a piece of rubber hose to the forward most hole in the sensor. Now carefully take a small safety pin and stick it in behind the top wire parallel to the wire. You do NOT want to pierce the wire, only make contact inside the connector. This top wire is the active feedback signal wire. It will vary from 0-5 volts or so. The middle wire is ground. The bottom wire is 5-6 volts supply. Now the top wire voltage will vary as the pressure between the two holes in the sensor varies. Set your meter to read volts, either turn the key until the accessories are on or start the engine, either way is fine. Now using your mouth apply suction to the hose and you will see the voltage change from near 0 to near 5 if you apply enough suction. The vacuum on the hose should hold your tongue and not leak. If the voltage does not vary or is stuck high or low, the sensor is bad. Do the same thing to the rear port but the voltage difference will be much less, this is the reference port.
If the sensor seems to be working then you can further test the system by doing the following. Attach the hoses to the sensor as normal. Now remove the rubber vacuum hose from the top of the EGR valve diaphragm. With the truck running apply slight vacuum to the EGR valve and this will open the EGR valve. When the valve opens you will see the voltage on the top wire of the DPFE sensor change indicating flow. When the vacuum is applied your truck should stumble or almost stall indicating the EGR valve has opened which it normally does not do at idle. I hope this helps.
Remove the 2 rubber hoses from the bottom of the sensor. Attach a piece of rubber hose to the forward most hole in the sensor. Now carefully take a small safety pin and stick it in behind the top wire parallel to the wire. You do NOT want to pierce the wire, only make contact inside the connector. This top wire is the active feedback signal wire. It will vary from 0-5 volts or so. The middle wire is ground. The bottom wire is 5-6 volts supply. Now the top wire voltage will vary as the pressure between the two holes in the sensor varies. Set your meter to read volts, either turn the key until the accessories are on or start the engine, either way is fine. Now using your mouth apply suction to the hose and you will see the voltage change from near 0 to near 5 if you apply enough suction. The vacuum on the hose should hold your tongue and not leak. If the voltage does not vary or is stuck high or low, the sensor is bad. Do the same thing to the rear port but the voltage difference will be much less, this is the reference port.
If the sensor seems to be working then you can further test the system by doing the following. Attach the hoses to the sensor as normal. Now remove the rubber vacuum hose from the top of the EGR valve diaphragm. With the truck running apply slight vacuum to the EGR valve and this will open the EGR valve. When the valve opens you will see the voltage on the top wire of the DPFE sensor change indicating flow. When the vacuum is applied your truck should stumble or almost stall indicating the EGR valve has opened which it normally does not do at idle. I hope this helps.
so i just conducted the above test on my 1998 expedition 4.6l (Windsor). my DPFE passed the first part of the test as i measured jump in voltage from about 1 to 5 on the forward port and a change in voltage on the rear port. i plugged hoses back and applied vacuum on the EGR valve but no change in engine idle and a very slight change on voltmeter connected to the top DPFE connector. Does this mean my DPFE is good and the problem is the EGR valve? or at least that the DPFE is good or bad? anyone?
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I should also add that one of the rubber hoses, connecting DPFE to the metal pipe coming of the exhaust is damaged at connection so I will need to replace that but shouldn't the EGR valve open anyway?
my truck might have several issues (i just bought it with cel on and i got p0401, p0171 & p0174) but at this point i want to eliminate some parts and narrow down to problem(s)
my truck might have several issues (i just bought it with cel on and i got p0401, p0171 & p0174) but at this point i want to eliminate some parts and narrow down to problem(s)
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Joined: Dec 2010
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DPFE Gnd. return from PCM
This is what seems to happen on DPFE sensor checks---you can test the EGR @ idle w/vacum and watch the Vdc (from Gnd wire on DPFE to SIG wire on DPFE) go from .9 to 2or3+ Vdc. This seems to verify EGR diaphram is good. After verifying that, now the Vdc @ DPFE from Gnd wire to REF wire should read 5Vdc. This Vdc comes from the PCM. You need to also VERIFY you have a Vdc RETURN signal from the PCM. With the multimeter probe on DPFE Gnd, take the other lead to battery NEG (-). If you do not have the 5Vdc Gnd reference from the PCM, these devices (EGR/Vac.solenoid/DPFE) will test good all day long, but the EGR will never operate under this condition. What makes it an Xtra asskicker is if the Gnd return from PCM is intermittent. So many variables but my new EGR & Vac. Solenoid were needed, but I don't think my DPFE was needed, R&R'd the new back to old DPFE and all tested fine. With the Xception of the RETURN Gnd from PCM. This is still intermittent & trying to find an open/short on the Gnd back to PCM is a challenge. I hope this helps....
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DPFE & EGR fixed?
Well after last post did not get much done but did continue some testing...Seems to me I had/have a Gnd. return problem from PCM to sensors...EGR bench tests fine in cold/warm a.m. but after more road testing it picked up sporadicly & would eventually not pick up at all. Finally saw it pick up occasionally only to see it leak down from 3in Hg. Replaced that. EGR vac.solenoid would operate the same way, intermittently. Replaced that. Finally Replaced DPFE but lost the Gnd. return from there back to PCM. I figured I would just dedicate a different point on PCM for it's own dedicated Gnd. since this is not a chassis Gnd. Messin' round, with new DPFE,EGR,& solenoid the vacuum gauge now picks up (3in Hg) at slight throttle @ any speed, and drops to zero which seems correct. No CEL after the last lean banks 1&2...Only problem is I still don't have a return Gnd. to PCM from DPFE...How can that be? I would think a new CEL would show no return Gnd. or since I don't see it durring testing, how am I getting to 3in Hg @ EGR input? Should it be closer to 5in Hg? I only can get 600-650rpm @ idle when engine @ op temp. but it's not hunting anymore...for a 5.4L V8 w/157,000 is base idle approx. 800rpm? I am going to look for the SPOUT this a.m. but first is Emissions testing....Boy I'm winging it for now!.....any imput is appreciated!
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Joined: Jan 2011
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Well, problem with my EGR system was a clogged EGR valve. Those two passage lines leading from the valve to the intake were completely clogged. I cleaned and the valve now opens and closes. At this point I am assuming my DPFE works because after cleaning the passages, I no longer hear clicking/tapping sound when power is demanded from the motor.
sorry Ford-N-floored, I can't help with your issue. You seem way more knowledgeable than me anyway
sorry Ford-N-floored, I can't help with your issue. You seem way more knowledgeable than me anyway
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Thanks "cx3gma" for your fix...I did replace those lines yesterday as a matter of fact..Had to get the emissions test done finally...was not sure if I would pass due to the issues I have...but I passed! Maybe a "pay it foward" from the employee after me telling him the issues...Anyway, still no Gnd. return to the PCM but the vacuum gauge hooked up for the drive testing part shows @ 3in-Hg on soft throttle then returns to Zero when let off or when I stomp on it at any speed...was told by a Ford mech. at the auto store that it sounds like its working, but should be closer to 5in-Hg and my Idle at 600-650rpms should be closer to 800rpms at Idle...told me to recheck vacuum system and the CKT & CHT sensors...then go on to looking at the base Idle issue with the SPOUT removed...we'll see, hope anyone can offer some more input, always appreciated!