EGR Valve?

What was the codes ?
most common EGR PRESSURE FEEDBACK SENSOR

Just changed the EGR and the DPFE sensor. These lines don't add up. I have the diagram here and it doesn't make sense. It's almost like I'm missing a line. In my photo the red line has a 90 deg bend into the intake, and also there is a red line coming from a solenoid next to the fuel rail. That red line ends. Open? I have 2 fittings here I found sitting on the transmission. One with green plastic but the plastic line is hooked up.

Okay, I may have jumped the gun and asked this question, I found the remainder of the line which is a connector to the rear of the intake with a red line. However the picture with 2 fittings I pieced together to join the remainder of the red line together. Is that how it is supposed to go? It seemed to run fine. My engine light is staying off but for some reason when I do an OEM Enhanced scan it shows P1519 showing up.

Hello,

I have included the vacuum hose diagram for your vehicle in the diagrams down below. The DPFE sensor should just have an electrical connector and two hoses that go to the exhaust manifold as it measures the exhaust pressure in your vehicle. There should be no vacuum lines going to it. I hope this helps.

Thanks,
Alex
2CarPros

Has nothing to do with the DPFE, only the green and red plastic lines going to the intake, FPR, EGR, and solenoid. I pieced those two black plastic fittings together to join the remaining red line.

The car starts and shoots to 2,000 rpm's, then sits at 1500 for a few seconds, and finally rests at 700-800 rpm's. Is that okay? Feels like it has more power after this new EGR and sensor, does that make sense?

Hello,

Yes, it is okay. What is going on is the Power-train Control Module [PCM] has the timing retarded so the combustion event is happening much later to actually get it so it is happening that fire is actually going out the exhaust valve to get the O2 sensor[s] up to operating temperature as quickly as possible so it can switch from open loop operation to closed loop operation. When the rpm's do this, it is the PCM controlling the Idle Air Control [IAC] valve operating the engine rpm's as needed. This is normal for this year of vehicle. My 1997 Mustang GT does the same thing.

Thanks,
Alex
2CarPros

Okay, well it didn't do it before the new EGR, DPFE sensor, and hoses. So could this mean that the vacuum is better and that this is a good thing? Or the opposite?

Hello again,

Okay the Exhaust Gas Circulation [EGR] valve should be closed and only recycles exhaust gas when at cruising speeds like going down the highway. If it was open at idle your vehicle would stall because there is just enough air passing the closed throttle plate to keep the vehicle idling through the Idle Air Control [IAC] valve. The DPFE is a sensor that deals with the exhaust pressure and doesn't have any vacuum lines attached to it. The EGR valve is vacuum controlled through the EGR vacuum control regulator which is a PCM controlled vacuum one way gate. I don't know why it wasn't operating in open loop before, but, I assure you, this is how this years vehicle's are supposed to operate.

Thanks,
Alex
2CarPros

I fixed the above vacuum lines but I'm still getting a P0401 code. I replaced the EGR valve, DPFE sensor, and exhaust hoses going from the sensor to the EGR tube.

Hello again,

In the diagrams down below I have included the diagnostic troubleshooting guide for DTC P0401 from the vehicle manufacturer. Please go through the guide and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

Seems like p0401 may be intermittent. What does HE90 say? It may come on after a couple weeks, or months, sometimes every other day. It's never consistent. I almost think it's the control solenoid because that's the last thing to replace. I don't have vacuum gauges and you can forget getting a multi-meter on the DPFE sensor.

Hello again,

Okay, so I have included HE90-92 in the diagrams down below. Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros

There's nothing there.

Hello again,

I'm sorry about that. This happens to me from time to time. Here they are. A little trick that I've used before is where they want you to install a breakout box is to use the PCM electrical connector and small safety pins instead. The breakout box is a box that goes inline in between the PCM connector and the PCM with big holes for every pin on the PCM. You can stick the leads of your DMM into the holes and it is the same thing as inserting them into the PCM connector, but without the possibility of damaging the PCM electrical connector. Using small straighten out safety pins, and I emphasize small, you should be able to insert the safety pin into the corresponding PCM electrical connector female pin and then touch with the DMM lead and accomplish the same thing. The small safety pin will fit snug and will not damage the PCM electrical connector female pin. This is extremely important and please be very delicate when you do this. Please get back to us with what you find out.

Thanks,
Alex
2CarPros

Well, the light hasn't come back on yet. I cleaned the EGR port on the intake. It was pretty dirty. Also, I found that a metal arm attached to a lever was disconnected. It looks like the lever is attached to an "intake manifold runner control valve", Part # 911928. This arm is held in the lever by two little white bushings (part #47099). Do you think that has anything to do with it? The car seems to start right up very quickly now.

Hello again,

Absolutely. The intake manifold runner control is vacuum operated and if there is a leak there, then that's a vacuum leak and that would cause your vehicle's symptoms.

Thanks,
Alex
2CarPros

Visiting this again because it's still happening. Read something somewhere about the C channel might be clogged. Look at this! This apparently goes right to the EGR. Hope cleaning this will do the trick.

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
Possible Solutions In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
Clean out the EGR valve and/or tubing to remove deposits
Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
Replace the DPFE sensor (with a good quality / OEM one)
Replace the EGR valve

You found the problem my friend, nice work. Let us know when happens after you clean it.