97 EGR low flow code

[bobdilts]

I'm getting this code. replaced the valve ($50 Autozone) but the code came back. Anyone have any experience with this. anything else i should be looking at?

[TaurusKing]

What code number???

[way2old]

Bet it is a P0401.

[shorod]

I think way2old is correct.

Per the service manual:
Diagnostic Trouble Code (DTC) P0401 indicates that Continuous Memory Self-Test has detected insufficient EGR flow.

Possible causes:

-- Fault in vacuum supply to EGR vacuum regulator solenoid.
-- EGR valve stuck closed or iced.
-- EGR valve diaphragm leaks.
-- EGR valve or flow path restricted.
-- EGR vacuum hose off, plugged or leaks.
-- VPWR circuit open to EGR vacuum regulator solenoid.
-- EGRVR circuit to PCM open.
-- EGRVR circuit to PCM shorted to PWR.
-- Differential pressure feedback EGR (D.P.F. EGR) sensor pressure hoses both connected improperly.
-- D.P.F. EGR sensor pressure hoses reversed.
-- D.P.F. EGR sensor VREF circuit open.
-- Downstream pressure hose off.
-- Downstream pressure hose plugged.
-- Damaged orifice tube assembly.
-- Damaged EGR vacuum regulator solenoid.
-- Damaged D.P.F. EGR sensor.
-- Damaged PCM.

-Rod

[bobdilts]

You guys rock. I'll get on that list and report the results.

Thanks!

[mwt878991]

AZ will alwaystry to sell the EGR based off that code and it is more than likely the DPFE sensor as previously mentioned.

From what I have personally experienced moisture gets inside the sensor and causes it to screw up.

There have been many threads on different boards about this.

Also the cost seems to vary by location.

I paid like 38 dollars for my 2000 durtec but people say the vulcan is more expensive.

Anyway it seems the Ford Dealer usuall has the best price on it

When I had my computer reprogammed I just had them turn that off

Mike

[bobdilts]

It was the DPFE sensor. Easy to replace, $49.00 at autozone. No codes and much better acceleration. Thanks for all of your help.

[way2old]

Thanks for the reply. Glad you got it going.

[davew91]

I would suspect this may be the same case in a '91 Taurus ?

I got the same code, bought the EGR valve, haven't installed it fortunately, and can return it.

3.0 L V6, not sure if this is the same motor they still used in the '97.

I am going to try the DPFE sensor based on your info. Really glad I saw this post, was going to do the job this weekend.

Thanks.

[davew91]

Ok, ran out and got the solenoid/sensor, very easy fix as others said. The light went out for a while, I was happy, then a bit mad, say 5 minutes, and after driving for a while, it came back on. My next task will be to pull the EGR valve, and look for crud buildup, and give it a crude check by sucking on the vacuum inlet to see if the valve operates. If it checks out bad, I will replace and see if thats the trouble. Stinks since I just traded the part it for the sensor

Original part, I suppose it could be bad. 135ish K miles on it. I have also heard that the orifice can crud up over time, so I will investigate and de-carbon/sludge the orifice. Vacuum lines all seem ok.

If anyone else has advice, please help. Do I just need to drive the car for a while to have the codes clear and the computer readjust? Its a 'volatile' or key-on memory fault code, light comes on after the car runs for a while.

[davew91]

Ok, again I comment.

Since the code came back, I replaced the EGR, it was in sorry shape, rusty, and lots of debris inside. I suppose I could have cleaned it out, but being that it was old, I tossed it.

Code is gone.

Funny thing happened. I inadvertently snapped the sensor tap on the EGR hose off. Thinking I botched everything up, I figured the light would come back on. It didn't. So.... I probably never had a bad sensor to start with, and should have gone for the EGR valve the first time around. Ended up spending $$ I didn't need to.

Strange however how without the pressure tap on the sensor connected, the light isn't on. I drove the car a good 10 miles also, and it was good and hot. I will try to re-attach the tap sometime with some J-B Weld. Does the tap activate the EGR ? would think so, but with an atmospheric reading, it apparently causes no fault code.

BTW, the tap was rusty, and very clogged with carbon, simply cleaning it out may help before replacing sensors/valves. May just plug the EGR tube hole up and forget about it. Cars old anyway, and as long as it is emissions legal, who cares.