Sensor problem question

[Diggity UW99]

I recently had my check engine light go on. After trying to pull the engine codes myself, I couldn't narrow it down because I got codes for ECT, IAF, EGR and TP sensors. When taking it in to Ford, they came up with MAF and PFE sensor. My question is: How crucial is the PFE sensor and what adverse drivability symptoms can it cause (because I haven't really experienced many). Also, could a faulty MAF cause some of the other sensors to read wrong, but not show a code for the MAF itself? I am pretty sure that the MAF can be bad because I had an encounter with a very large puddle which soaked my air filter as well as MAF; however the check engine light came on a month or so later.

Dan

 

[TPLYNCH]

Dirty MAS can cause a cascade effect. So can a bad/dirty DPFE. Try cleaning the MAS, reset the computer and see what happens.

 

[StalkExplorer]

Do you have any update on your problem? I would suggest that it may be a bad ground connection as at least three of the sensors (TPS, ECT and IAT) all share a common ground connection (from the Haynes manual pg. 12-24)... I'm not sure where to look for this though, because both the signal to the computer and the ground are in the harness... I would only sugget to follow the grounds from the battery and look for rusty or bad connections...

 

[MaverickDaKid]

me too

I have this problem also, but I took it to my mechanic and he said it was a dirty sensor or something like that. He cleaned it off and the light went off. 30 mins later it went back on

He said I could drive it around like that and it wouldn't affect my performance. He took a look at everything else and he said it was all perfect, well except this one weird sound I got going but its barely noticable and he said its part of the temp control system. And that it won't affect performance or anything else.

Anyways I am thinking of replacing it because the light annoys me. That and everyone who steps in my truck thinks something is wrong with the light on.

So I am wondering how much the part costs. And how much does it usualy cost including labor.

 

[dogfriend]

Originally posted by Diggity UW99
My question is: How crucial is the PFE sensor and what adverse drivability symptoms can it cause (because I haven't really experienced many).

The PFE sensor (or DPFE, depending upon which version you have) is a sensor which monitors exhaust gas pressure. The computer uses this information to compute the flow in the EGR system. There are a couple of different scenarios possible:

1. The PFE or DPFE sensor is bad (or the wiring is damaged). The EGR is still working properly. This would light the CEL without causing any driveability problem. See this thread:Dead Link Removed

2. You could have a cracked hose or leak causing the sensor to read incorrectly. This may or may not cause driveability problems depending upon how bad the leak is. Look for the leak in the EGR system.

3. The EGR valve is sticking or leaking. The EGR valve should only be open during " warm cruise" operation. If it is open at other times, this would be detected by the PFE sensor. You would probably see some driveability issues (poor idle) if it is stuck open. You may see increased emissions (the reason for the sensor, it confirms operation of the EGR system) if the valve is sticking closed. It would also throw off the fuel/air ratio in "warm cruise" if stuck closed.

 

[Diggity UW99]

Sorry about the delay, I haven't checked my e-mail in a while. I could not locate the problem myself so I took the vehicle in to have it diagnosed and I had a bad MAF as well as a bad PFE sensor. The MAF was only $100 from Schucks Auto Parts (Ford wanted $300) but nobody had any idea what a PFE sensor was so I had to get that part from Ford. I think they charged me about $140 for it or something I can't remember. The new MAF didn't turn the light off but replacement of the PFE sensor did. So, I am not actually sure that the MAF was bad but it wouldn't suprise me since I had sucked water into the intake a month or so earlier. But then again, why didn't the check engine light come on earlier? If anybody is having these problems, I would recommend changing the PFE first.

Dan