So the Service Engine Soon came on in my truck yesterday. I was able to get into Advance Auto Parts before they closed and they were able to read the error messages. They said it was either the EGR valve or the EGR pressure feedback sensor. The error messages were "EGR low voltage, EGR low input flow". He did show me where it was located, but how do I know which of the parts is bad or is there something else I should look for? Do I need more information to determine which part is faulty? Thanks.

 

We need the DTC code, it comes up on the scanner after they plug in. - can't help without one -PO4?? - Fill the question marks in.

It must have an engine - which one man ?

Need info.

 

Ok, will get exact error codes later today. Engine is 5.4L

 

Just got back from checking error codes at another location and they turn up same results. Error codes are P0401, P0405 and P01405. All EGR related. He suggested to replace the EGR valve, but I did some checking on net today and it seems the DPFE sensor is the most common culprit. Assuming it will be the DPFE sensor I called around for prices today and got a wide range of prices. Ford dealership wanted $129, NAPA wanted $86, Autozone wanted $48, and Advance Auto wanted around $70. Is there anything to check before changing the DPFE sensor? Which place would have the most reliable part?

 

Yea but you have a 1405. That's uncommon. The DPFE Monitor checks the integrity of the DPFE signal hoses. The test is run during a period of acceleration, when the PCM commands the EGR valve to close momentarily, and then checks the DPFE signal for a voltage consistent with zero flow. A voltage increase or decrease during acceleration indicates a fault with the hoses during this test.

1405 indicates "Plugged", in this context means blocked - A blockage by foreign matter, kinking or melting which stops the gas flow. It is not difficult for work on the engine to knock off a sensor pipe either.

Could very well be the sensor - check the hoses first before purchasing the DPFE. Pull the hoses from the sensor only. You should be able to blow thru them both while still attached to the pipe. - If not , prolly plugged at the orphis. Coat hanger it

BEWARE!

Do Not purchase THIS particular sensor from anyone but the dealership. Trust Me - The other vendors carry a sort of knock-off replacement that doesn't last long.

 

Well, I popped open the hood tonight to see how difficult it would be to change the DPFE sensor. I was astounded by what I found! The DPFE sensor ends were melted and the hoses were laying on top of the engine. Hoses were cracked open and burned. Looks like new sensor and a couple of new hoses should fix the problem. Anyplace else to get the OEM Ford replacement part other than the dealership? $129 is a lot to pay for that little sensor!

What the DPFE sensor looked like when I opened the hood



Hoses laying on top of engine. They connect to DPFE sensor



Cracked and burned hoses



Bottom of DPFE sensor. Plugged hole is REF port and open hole is HI port.

 

Great pics! Yea, you better get your cats checked - that's what causes that. I would "suck test" the valve - make sure it's operational. Not good- check the cats at the dealership

If you need replacements - GET your old ones back. There worth $200 believe it or not at the scrap yard.

 

You can get them at Napa, Autozone, O-o-o-oreilys...for about half of that.
















But you will be replacing them every month.

 

the dealer and napa have updated dpfe sensors. there not much better than the one that came out of your truck but there still updated. and get the hoses from the dealership because anywhere else you get them from will have cheap hoses that wont handle the heat.

 

These DPFE sensors are nothing more than a ceramic, capacitive type pressure transducer. The sensor outputs a voltage to the PCM in direct proportion to the pressure drop across the orifice in the EGR pipe. In this way the PCM can make an accurate assessment of the gas flow through the tube. It has nothing to do with the problem you have. The sensor was compromised do to another issue. Yes, you need a new one. I informed you where to purchase as well - Just keep that in mind.

Now your EGR valve increases or decreases the flow of exhaust gas into the inlet manifold and this is by a diaphragm operating on a pintle which is connected to a poppet valve. When no vacuum is present, the spring keeps the poppet valve closed. - Guess where all that exhaust heat transfers to?

When working correctly the EVR allows sufficient vacuum to the EGR valve, the vacuum pressure overcomes the spring and the poppet valve opens, but as soon as the vacuum pressure is reduced spring pressure closes the poppet valve again. I don't think yours is even opening for some reason. I could be stuck or the 3/16 -1/4" vacuum harness (look @ the EVR) is damaged.

In general, your engine is suppose to use Exhaust Gas Recirculation to reduce combustion temperatures in the cylinders at part-throttle and this reduces the production of Nitrogen Oxide gas to levels manageable by the Catalyst so that very little escapes to atmosphere. If it's not functioning properly, your DPFE is taking ALLOT of heat, as you can see.

Like I said -Suck test the EGR valve. Better check the vac harness; the EVR needs vacuum to trigger the poppet when the PCM commands.

It could be one of your converters, not likely, but it doesn't hurt to check them. The rear (down-stream) usually when the forwards start to go - comb material contaminates the rear and interrupts flow. Then everything from the downstream converter forward gets hot!

Throwing a new DPFE Sensor on there at this point would be a bad idea until you dig in and find what caused it.

Good Luck

 

Update. Received DPFE sensor and fuel filter in mail today. Ordered both through directfordparts.com. Probably saved about $45-50 versus local Ford dealership even with shipping costs. Ordered Wednesday and received today. Very pleased and I encourage people to check them out first before getting parts anywhere else. I did have to pick up the vacuum hoses at the dealership since nobody else had them. Before I put the DPFE on, I did a suck test on EGR valve by attaching tube to top of valve and sucking in. Motor started stumbing and almost died and figured EGR valve and throttle body holes were ok. I did try to check the filter on EVR, but I couldn't figure out how to get cap off top of it and I didn't want to break it. Looks like it needs a screwdriver to pop it off like caps on spray cans?? Finally, put the sensor in, started it up and check engine light was still on. I took it to Advance Auto and they reset the codes. I ran around for 10 miles and so far light hasn't come on yet.

jbrew, how much does it cost to check cats at dealership?

 

you will usually know when a cat goes bad. they either rattle or you will lose power or your truck will hesitate or will only reach a certain speed.
and i see dpfe sensors go up all the time on fords. most of the time they melt and the hoses rot and rip, just like yours did.

 

I can't think of anything else that would cause this problem, but I too have seen it before - Only on explorers tho. I've heard of it happening on our trucks as well - just haven't seen it yet.

Well, you haven't mentioned anything about your vac harness. It covered in plastic coil shield that pulls off. What happens is those little plastic vacuum lines become brittle over time and break inside the sleeve. Matts ford may have seen that happen if he's a tech or works on them often.

Do you here any humming noises under the hood after shut down ? The EVR will do that at times. Actually that's a good sign that your vacuum system is intact. - Humming is normal and to determine it's origin, just place your hand on the EVR while it's humming - You'll feel it vibrating.

Anyway, your EGR valve sounds like it's good, but is it getting enough vac to supply to the valve itself ? You'll produce a another check engine if it's not, it throws a the MIL after about 3 or 4 drive cycles after a fresh reboot.

If your light stays off then I would say your good to go. However, if it comes back on, address it ASAP.

Good luck and thanks for using the search bar - I can tell you have