Question about the EGR valve and Code 337

[Dash Riprock]

95 XLT 4.0 OHV

The CEL came on recently with no change in performance or drivability.

Checked codes and got:

KOEO: 337
KOER: 337
CM: 337, 122

The 122 is a TPS low code, one that I have had in the past (http://www.explorerforum.com/forums/showthread.php?t=159369).

337
(O,R,M)
EGR feedback signal is/was was high - EVR

This past weekend I did the much debated TPS voltage adjustment, initially found it to be .90 vdc, and adjusted TPS to read .98 vdc. After disconnecting battery and driving, the CEL relit, with the 337 code repeating in KOEO, KOER, and CM, but the 122 code gone. (Somehow I doubt this was the source of the 122 code, we'll see)

My DPFE was replaced last July.

So, what does a code 337 ask me to do? Is there a standard procedure to fix this? Simply replace EGR valve after checking wiring?

My wife actually took this for her smog check while the CEL light was on and it passed.

Hints and suggestions welcomed. Thanks

 

[BrooklynBay]

Maybe the EGR is defective (stuck), or the inlet is clogged. Check the vacuum line going to the DPFE for a leak. Moisture kills the DPFE.

 

[Dash Riprock]

Maybe the EGR is defective (stuck), or the inlet is clogged. Check the vacuum line going to the DPFE for a leak. Moisture kills the DPFE.

Ill do that.

Im wondering what the actual effect is of the fault. What happens if I ignore it and drive around with it sending this code? So far, I cant see any difference in how the engine behaves. hey it passed smog, how bad can it be?

Knowing me though, Ill keep tinkering with it.

 

[BrooklynBay]

Here is a thread which you should find interesting: http://www.explorerforum.com/forums/showthread.php?t=164517

 

[Dash Riprock]

Thanks Brooklyn. What pisses me off is that my DPFE is less than a year old, and I didnt keep the receipt!

Still, Ill check the EGR valve and do the vacuum troubleshooting and see what pops up.

 

[Dash Riprock]

Just an update to this.

I changed the DPFE, again, and it fixed the problem. The reason I was looking deeper is because I didnt think a one year old DPFE would fail.

The unit was from Autozone by the way. Ill see if the replacement from them fairs any better.