Code 337, DPFE?

[tbs1967]

94, 2wd, 4dr. CEL with code 337. Measured DPFE voltage with ignition engine off and reading was 5vdc. Engine running at idle same voltage reading. I cranked up the rpm and again same voltage.

My million dollar question, should the DPFE voltage coming out be near 0 vdc when engine off or idle?

Also, can a bad DPFE cause hard start when cold? And reduced gas mileage?

 

[tbs1967]

Problem solved. I replaced dpfe sonsor in the summer of 2012 and a heads up employee at Autozone indicated it's a lifetime warranty saving me $53! I took it out and plenty of burn marks.

Truck starts up easier when engine is cold, smoother running, and I hope to get better gas mileage. Also, to answer my own question about voltages, the following link gives the expected voltage reading of dpfe voltages and theory of operation. Excellent link.

 

[tbs1967]

http://rockledge.home.comcast.net/~rockledge/RangerPictureGallery/DPFE-Voltage-Test.html