Two EEC codes... what do they mean?

twinturbostang · Post by **twinturbostang** » Mon Jul 23, 2007 6:29 pm

On my '00 Expedition, I'm getting P1405 code:
Differential Pressure Feedback Sensor. Upstream hose off or plugged.

And on my '97 Cobra, I'm getting P1401 code:
Differential Pressure Feedback High Input.

Are these EGR related? I don't have anymore explanation on the codes than that. In the case of the Cobra, the EGR has been purposely removed, and (I thought) disabled in the EEC. So it's surprising I'm still getting a code for it. For the Expedition, I have no idea, since all systems should be properly installed.

Thanks guys,
Brian

Post by **cgrey8** » Mon Jul 23, 2007 6:59 pm

The Differential Pressure Feedback Sensor (DPFS) is the sensor used to regulate EGR position. The Expidition code can be fixed by verifying that the hose is properly connected to both the sensor and the EGR line tap. Also verify the line isn't cracked which could mess with the pressure readings. If all else fails, replace the DPFS.

On the Cobra, it sounds like the EGR hasn't been completely deleted if it is still looking for feedback from the DPFS. But then again, I guess it's possible the EEC is still monitoring the DPFS, even though it isn't controlling anything based on the feedback it gets from DPFS. You'll have to find out from someone that knows your EEC better for more details on that.

JuiceSC · Post by **JuiceSC** » Tue Jul 24, 2007 11:49 am

Make sure your egr is working (if still there). I just fixed my mom's car with that code. The passeges under the TB were totally clogged with carbon.

Sensor~$85

Cleaning=freee

twinturbostang · Post by **twinturbostang** » Tue Jul 24, 2007 11:56 am

Thanks. I will have to check the EGR on the Expedition. Maybe one of the hoses popped off or split.

I'll also check the tune on the Cobra and make sure EGR is in fact disabled.

Juice: Which code were you referring to?

twinturbostang · Post by **twinturbostang** » Wed Jul 25, 2007 11:29 am

I checked the tune on the Cobra last night...

EGR System Type = 0

I'm assuming that is correct, although I have seen EGR set to 0, 1, or 2 in some tunes. Not sure what type = 2 does. Anyone know if I have this set correctly, and whether or not there are other scalars that need to be set?

Thanks,
Brian

Post by **cgrey8** » Wed Jul 25, 2007 11:47 am

In GUFx EECs, this is a breakdown of the types:

Type0 is normal Position sensor feedback also referred to as the Sonic system.

Type1 is Pressure-Feedback EGR (PFE) not to be confused with the newer Differential Pressure Feedback EGR (DPFE) systems which is what the Expitidion no doubt has since it has a DPFE sensor.

Type 2 is no EGR system installed.

Not many vehicles used Type 1 EGR systems that I'm aware of, but I have heard and read about it. Most all the EGRs I've ever dealt with were direct-position sensed (what Mustangs have) or the newer DPFE which came out around the OBD-II days. Some 95 Fords had it like the 95 4.0L Rangers which were OBD-II compliant a year early. But other vehicles didn't get DPFE until 97 like the V8 Explorer motors.

twinturbostang · Post by **twinturbostang** » Wed Jul 25, 2007 12:50 pm

Ahh!!! So it sounds like I actually have it configured incorrectly then, for removed EGR. I will set it to 2 and see what happens.

Thanks for the info!! :D

edit: BTW, the stock LLX4 ('97 Cobra) tune shows EGR system type = 1. So the new(er) Mustangs must have that newer EGR system.

Post by **cgrey8** » Wed Jul 25, 2007 12:53 pm

Again, that's for GUFx. If you aren't using an EEC that follows the same rules as GUFx, then a value of 2 may mean something else. I'd hope Ford would standardize on that, but I'm not about to assume they did. But it's worth at least testing if you got nothing else to try. Good luck with that.

twinturbostang · Post by **twinturbostang** » Wed Jul 25, 2007 12:56 pm

Right. This is the CDAN4 strategy. So maybe it is different. Oh well, I'll try it and see. I have to go through emissions, and I think for the OBD-II cars they just plug it into the computer (no dyno rollers anymore). Having the check engine light on may result in an immediate fail. So I've got to figure out how to get EGR disabled.

Post by **cgrey8** » Wed Jul 25, 2007 1:07 pm

If the OBD-II emission tests are nothing but plugging into the computer and having the computer feedback a "PASS" code to the emissions station that the computer is happy, it sounds like OBD-II makes it far easier to pass emissions even when you are far from being in compliance. Things like EGR and the after-CAT HEGOs are easy to turn off from what I understand.

However what nobody's been able to tell me is if part of the OBD-II emission test includes queries to the EEC to verify that things like EGR and after-CAT HEGOs are still activated in the tune. If the emission station tests are sophistocated enough to detect custom tunes, then simply turning it off in the tune may also fail you. I guess you'll be finding out...

twinturbostang · Post by **twinturbostang** » Wed Jul 25, 2007 2:52 pm

cgrey8 wrote:However what nobody's been able to tell me is if part of the OBD-II emission test includes queries to the EEC to verify that things like EGR and after-CAT HEGOs are still activated in the tune. If the emission station tests are sophistocated enough to detect custom tunes, then simply turning it off in the tune may also fail you. I guess you'll be finding out...

Yeah, that definitely is a concern. And I guess I'll find out. I plan on taking it in tomorrow morning, so I'll let you guys know what happens.

I took my Expedition in for emissions maybe a year ago, and they did the computer "plug-in" test. No dyno roller at all. At the time, the check engine light was not on (that's just recently come on), and it "passed" just fine. But I too am curious as to how sophisticated the OBD-II tests are.

steelborn1 · Post by **steelborn1** » Thu Jul 26, 2007 8:27 am

You will most likely need to replace the sensor on the Expedition. The factory ones are made from pewter and corrode easily. Replace it with a plastic aftermarket one. I see these things on a daily basis. I think it is one of Ford's lowest bidder parts.

bricklin · Post by **bricklin** » Fri Jul 27, 2007 6:23 am

Check with your ford dealer, There is a TSB on the sensor and some will be replaced free by the dealer.

Two EEC codes... what do they mean?

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