steadyhand
Active Member
- Joined
- May 5, 2010
- Messages
- 98
- Reaction score
- 0
- City, State
- Missouri
- Year, Model & Trim Level
- 99 Mercury Mountaineer
Sorry for the lengthy post but I like to get as much detail out as possible. I did google this so I have some information and understanding, but I'm still a bit confused. I'm hoping someone can help me make sense of this before I start spending money.
My cel light came on yesterday and I immediately stopped by autozone to have the codes ran and got code P0401. My google searches are saying it has something to do with the EGR or possibly the PDFE sensor.
I checked on a couple things first.
1.When I unplug the EGR, nothing happens. The engine idle does not change.
2.When I apply vacuum to the EGR by sucking through a tube,with the engine running, the engine does almost die.
3. When I checked the hose that attaches to the EGR I noticed there is no vacuum when the engine is running, but I can blow through the hose. So there must be a blockage somewhere else.
4. When I apply a hose to the top port of the vacuum selonoid, I can blow air through the top and it WILL pass through out the bottom port which I believe leads to the manifold. When I blow air through the bottom port I get a noise from inside the selonoid and it does NOT seem like the air wants to pass through, so right now it only wants to go through one direction.
I did try to test the DPFE sensor with a voltage meter but not sure if I did it right. The plug to the DPFE sensor does have about 5 volts on the top and bottom wire (two outside wires) and the center wire I believe had .8 volts (key on, engine off test). I can't seem to get a stable reading when it is plugged into the sensor. It only flashes a voltage, which was never the same, and then goes to zero.
Anyway this is all I've checked so far. If you can make sense of this and tell me the likely culprit and preferably why you believe that I would appreciate it.
I do not know a whole lot about the vacuum system, but I am confused as to why there would be no vacuum on the EGR. I thought if I unplugged the EGR and nothing happened that meant the EGR was clogged or defective, but if I apply vacuum when the engine is running it does work so that leads me to think it is not the EGR.
Threads on this forum seem to always point to the DPFE sensor for this particular code, but I thought the DPFE sensor only measured air passing through and thus wouldn't stop vacuum on the EGR.
What do you think?
My cel light came on yesterday and I immediately stopped by autozone to have the codes ran and got code P0401. My google searches are saying it has something to do with the EGR or possibly the PDFE sensor.
I checked on a couple things first.
1.When I unplug the EGR, nothing happens. The engine idle does not change.
2.When I apply vacuum to the EGR by sucking through a tube,with the engine running, the engine does almost die.
3. When I checked the hose that attaches to the EGR I noticed there is no vacuum when the engine is running, but I can blow through the hose. So there must be a blockage somewhere else.
4. When I apply a hose to the top port of the vacuum selonoid, I can blow air through the top and it WILL pass through out the bottom port which I believe leads to the manifold. When I blow air through the bottom port I get a noise from inside the selonoid and it does NOT seem like the air wants to pass through, so right now it only wants to go through one direction.
I did try to test the DPFE sensor with a voltage meter but not sure if I did it right. The plug to the DPFE sensor does have about 5 volts on the top and bottom wire (two outside wires) and the center wire I believe had .8 volts (key on, engine off test). I can't seem to get a stable reading when it is plugged into the sensor. It only flashes a voltage, which was never the same, and then goes to zero.
Anyway this is all I've checked so far. If you can make sense of this and tell me the likely culprit and preferably why you believe that I would appreciate it.
I do not know a whole lot about the vacuum system, but I am confused as to why there would be no vacuum on the EGR. I thought if I unplugged the EGR and nothing happened that meant the EGR was clogged or defective, but if I apply vacuum when the engine is running it does work so that leads me to think it is not the EGR.
Threads on this forum seem to always point to the DPFE sensor for this particular code, but I thought the DPFE sensor only measured air passing through and thus wouldn't stop vacuum on the EGR.
What do you think?
