2002 ST Codes P0401 & P0402 HELP PLEASE

[Tim OLeary]

Check Engine light came on and went to O'Reilly and the scanned and reset it P0401.
Then a couple of days later the Check Engine light came on, and went to O'Reilly's again and it said P0401 and something about being stored. They reset it.
After a couple days Check Engine came on again but went put after a day or so.
They finally delivered my FIXD sensor, and it reported both those codes, but the check engine light is not on.
So what is the best route to take towards repairing. There seems to be three components:
the sensor I bought one but did not use it yet (VP17)
The egr valve (says XC2E-9D475-A3A)
And another part the valve vacuum hos connect to.
The engine is running well but idles a little rough @ 500RPM.
I replaced the air filter, cleaned the throttle body, and the IAC valve.
The FIXD sensor and app are pretty slick, but lots of ads.
Any suggestions would be great.

 

[DILLARD000]

Year & Engine; assuming 2002 ExST V6~4.0L~SOHC?
p0401 = EGR Flow Insufficient
p0402 = EGR Flow Excessive
EGR DifferentialPressureFlowElement\DPFE Sensor is a NotoriousFailure Item,
& the 2 Hoses connecting the DPFE Sensor to EGR riser tubes, tend to wear\melt & leak.
"FIXD", is this an OBD2 Scanner? Not familiar with that one; have OBDLink Scanners here.
500rpm is a bit low; minimum idle should be ~650rpm.

 

[Tim OLeary]

Thanks For the feedback.
As I mentioned, I bought one of those sensors and I'll install and see if that's it.
the scanner was $20 returnable for 30 days.
https://www.fixd.com/home2/1-0?gc_i...3KnWXPVw9m7fGDyjDH-bVcgCSqVc122gaAr_OEALw_wcB

 

[DILLARD000]

That FIXD link in the fine print states
"Enhanced codes such as ABS, airbag, transmission, & TPMS are NOT supported." NOT good.
Best get an OBD2 Scanner that reads both StandardSAE & ProprietaryOEM TroubleCodes & Data.
Better options run $25~$150 depending on preference:
~ ELM USBModule or ODBLink#EX USBModule & ForscanForWindows
~ OBDLink#MXPlus BlueToothModule & OBDLinkAppForAndroid+ForscanForAndroid

 

[Todd Z]

Yup, Buy a DPEF sensor, Remove, Clean out tubes real well, replace with Motorcraft new sensor.

 

[Tim OLeary]

I installed a VP17 and it went well. The motor started, (no surge or stall), and now idles smoothly at about 1000RPM.
My mpg was a little over 15 b4, we'll see if it gets better with this new component

BTW:
2001 Ford ExST Job2 \ Engi=V6~4.0L~SOHC \ Tran=5r55e \ 4wTC=1354 \ Difs=4.10 \ http://2001fordexplorersporttrac.fandom.com
is awesome

Thanks!

 

[DILLARD000]

That's good news!
EGR DPFE Sensor, ValidSignalRange = 0.8~1.2vdc
StandardMotorProducts# vp17 or
FordMotorCraft# 4u7e-9j460-aa \ 4u7z-9j460-aa \ dpfe4

 

[Tim OLeary]

I spoke too soon, the engine idles at about 500 once warmed up, and typically idles roughly.
No check engine light. What could be another cause?
TIA

 

[DILLARD000]

Do you have any OBD2 TroubleCodes?
500rpms is too low for WarmIdle; should be 650~700rpms.
Suspect you've got a vacuum leak somewhere.
Once its warmed up with Engine idling & AC+Heat off:
~ set MinimumIdleScrew on right side of ThrottleBody so Idle is ~700rpms
~ unplug IACValve, RPMs should fall & Engine should sputter & may die.
If RPMs do NOT fall then you DO have a vac leak.

 

[Tim OLeary]

I disconnected the battery and after a while reconnected it and started the engine and allowed it to warm up. Then I took a little drive where the transmission would go through its shift points. My warm idle is now at about 750 and so I think it's working OK.
I will order a new code checker that was recommended and sent the $20 one back. The one I am going to get has a tach.
But I also ran into a problem changing the rear shocks. this one screw on the top driver's side; could not get a wrench on the nut. So I removed 5 bolts holding on what I am learning is a vapor cannister. There is a wire harness and a tube (which came off) while I was getting the thing to drop down out of the way so I could get at the inaccessible nut.
So now I hope the tube can go back on the cannister, and still works. Will it create a "check engine"?
TIA

 

[DILLARD000]

Any EVAP component failed\disconnected\leaking will likely generate TroubleCode(s) & CEL;
should not effect drivablity, but won't pass inspection & may result in a gasoline smell.

 

[Todd Z]

How old is fuel filter, plugs and wires ??? if over 30K miles or 3 years Replace them !!

 

[Tim OLeary]

You are right. That'll be the next thing. I also have a leak in a rocker cover gasket driver's side.
TIA

 

[Tim OLeary]

Changing the plugs is not progressing well. I got NGK plugs and Motorcraft wires. I requested a labor quote from mobile mechanic and so far got only one for $252.00.
So any tips on how to reach the plugs would be appreciated. I have a paved driveway but no lift; just floor jack jackstands and a pair of ramps. Are any special tools required to replace the fuel filter? Any preferred brand?
TIA

 

[DILLARD000]

Right side plugs are hardest to get to due to the AC Blower+Housing.
Put front end on jack stands, remove both wheels + lower skirts, to get to plugs thru wheel wells.
A good plug socket & selection of rachets+extensions works for me.
May want to spray penetrating oil around the plugs a few hours before.
Patience helps. Be sure to gap plugs; don't assume they're gapped correctly.
Click here for more info.

 

[Tim OLeary]

ARES 11008-3/8-Inch Drive by 5/8-Inch Magnetic Swivel Spark Plug Socket - 4-Inch Swivel Extension Permits Access to Most Confined Areas Amazon.com

 

[blert]

... Are any special tools required to replace the fuel filter? ...

One of these...

Scissor Fuel Line Disconnect Tool for 3/8 inch and 5/16inch Easy Separation of Quick Disconnect Style Fittings use on Fuel, Heater, and A/C Line Service Compatible with GM, Ford, Mazda Vehicles Amazon.com

 

[Doug Kaye]

$252 is a fair price for the work, I'd be tempted to take that offer ;-)

Did mine as per Dillard's notes. I have 3 sets of socket wrenches, and 2 sets of variable-angle extensions, and needed them all.

 

[Tim OLeary]

Thanks for your insights, Doug! Could you be specific about the socket wrenches and variable angle extensions?

 

[Tim OLeary]

So the plugs and wire replacement is on temp hold.
Instead I punked out and got the valve cover gaskets replaced. They did both sides.
The smoke had gotten intolerable, and I thought oil was perhaps getting on plug wires and contributing to the idling issues. (It still is idling a little low, but I drive this vehicle virtually every day of the week for about two hours a day, and it doesn't stall, it starts and runs, just the idle is a little funky.
Do I want to wash the engine, especially where the oil was dripping? There is oil down low in the pan area and I can deal with that next oil change, but it was also getting on the exhaust manifold. Also the whole engine area was sort of an oil suana and is a little "grimy".Should I let it burn off, or clean it off? Is tire foam good?
TIA