What component is bad in EGR codes.

[1993Saturn]

Trying to determine which sensor needs replacing as both do about the same thing, the EGR Vacuum Pressure Regulator Solenoid or the DPFE. I get 3 EGR codes. Obvious right now is a rough idle and running that comes and goes. So it could also be the Intake Manifold Temperature Sensor, which doesn't always show a code.

 

[410Fortune]

What are the codes?
The EGR pressure regulator, regulates the amount of flow the EGR allows into the intake
The EGR DPFE (differential pressure feedback) is a sensor that tells the computer how much EGR is flowing

They do not do the same thing

The IAT sensor motitors the temp of incoming air to the engine intake

 

[1993Saturn]

Sorry about not responding sooner. I had composed a response on my cell, but apparently it didn't post. There are so many ads that show up and you can't get rid of them they just keep coming back, blocking what you are trying to write.
Anyway, these are the codes I picked up:
226 - Ignition Diagnostic Module (IDM) signal not received (El)
327 - EGR Valve Pressure Transducer/Position Sensor circuit below minimum voltage
332 - EGR Valve opening not detected.
Now, I hate it when the book gives different names to parts than what the manufactures call them, so I want to ask:
is the IDM the Ignition Control Module located in front of the battery? And, is the Valve Pressure Transducer/Position Sensor the EGR Vacuum Regulator Solenoid with 2 vacuum lines.
As for the IAT sensor, I know it monitors the temp of the incoming air, but if it is faulty, then it could make my engine have a rough idle and running, which my engine is doing now, plus there is also a high idle and not coming down very often which inconveniently causes the vehicle to move forward without foot on the gas.

 

[410Fortune]

I would fix the egr codes first as they can cause the surging and high idle if there is a leak

327 = EGR position sensor below voltage
332 EGR valve opening not detected

To me it sounds like the PCM is not communicating with the DPFE and cannot tell if the sensor is there (no voltage being received) and cannot tell if the valve is opening (no feedback)

If it was not for the voltage code I would say the EGR valve is not opening, it is possible that both the DPFE and EGR valev are bad, or the plumbing to them
I would start with the voltage code, anytime a compute says "sensor circuit below min voltage" check the wiring to and from that sensor, check the EGR samepl tubes to and from that sensor
you can test the sensor or just replace it
The 1994 EGR uses a metal DPFE does it not? Aluminum body? Those DPFE plug up more easily then the later plastic ones.


IDM to me is something 7.3 powerstoke diesels use (injector driver module) lol
Let me look into this 226 code and report what I find. To me if the PCM truly did not get a signal from the ignition module (yes mounted in the inner fender on a 94) then your engine would not be running..

 

[1993Saturn]

The EGR pressure regulator, regulates the amount of flow the EGR allows into the intake
The EGR DPFE (differential pressure feedback) is a sensor that tells the computer how much EGR is flowing

Now you would think they could have made these sensors a 2 for 1. Instead, one tells the EGR how much to flow and the other tells the computer how much flowed. You would think the computer would know what it just did, after all, the Apollo Command Modules had smarter computers than that.
I have had to replace the ICM before because it's failure would make the engine on startup chug like a choo choo train. Restart a couple of times and it goes away. When I replaced it almost 3 years ago, the problem went away. Had the same problem again and since I still had the receipt, the warranty saved me from having to shell out $200 for a new one. Now I have no more chugging. So whatever goes wrong with those things, fortunately is multiple choice and doesn't just shut off signal to the coil pack.

 

[BKennedy]

The 94's did use a metal DPFE. I bought a new one years ago when my OEM unit failed. The new one failed out of the box. I went to Ford and they have a new replacement for the metal DPFE that is plastic, in a kit with new wiring for the different plug. It has been working fine for many years now.

 

[alaskan155]

i been chasing the dpfe/ egr for a while,

i have the updated plastic sensor from oriellies and a newer EGR...

my bet though is there is a solenoid that controls the vacuum on the egr, its the only thing i haven't replaced...

been to lazy to replace it as its not my Daily, but i bet it is the culprit if the other stuff is good.

 

[alaskan155]

on a side note, its too bad we cant use the egr sensor off a 88 bronco 5.0... that sensor checks the physical location of the egr valve.

 

[1993Saturn]

The 94's did use a metal DPFE. I bought a new one years ago when my OEM unit failed. The new one failed out of the box. I went to Ford and they have a new replacement for the metal DPFE that is plastic, in a kit with new wiring for the different plug. It has been working fine for many years now.

What happened that told you the DPFE was bad?

 

[BKennedy]

What happened that told you the DPFE was bad?

Check Engine Light came on, I ran the codes and it was the first thing I replaced. Light cleared after I went with the Ford DPFE kit so that was the issue.