Hey everyone, sort of newbie here, although not a new member. I've done all kinds of searches on the DPFE sensor going bad, replaced it and I'm still running into problems. My 01 with the 4.0 SOHC gave me the CEL about 3 weeks ago. It has 62K miles on it and had never been a problem before. The only error code I got was P1400. I went to Autozone and got a replacement DPFE sensor and bing, the problem went away, for about 1 week, then it came back. I wrote that one off as defective, so I returned it and got another one. It too lasted about 1 week before another P1400. I have checked the EGR valve, ensured the tube isn't blocked (at least 100% blocked) and I still have the problem. The only thing I haven't done is bought a new DPFE sensor from Ford, which is about $50. Any chance that the Autozone parts (Wells brand, I think) were sub-par and the Motorcraft will work? Or more importantly, what else might be causing these sensors to fail left and right all of a sudden? I have noted no other problems with the engine. The original sensor illuminates the CEL on KOEO, while the others illuminate within a minute or so of engine start and drive engagment. The Autozone parts are shaped slightly different than the original too, but everything else lines up. Any help appreciated.

Bryan

 

There aren't really too many things that can cause the 1400 code:

1. DPFE circuit short to GND
2. Damaged DPFE sensor
3. VREF short to GND
4. Damaged PCM

Based on the above and what you have done so far, it would appear there is either a problem in the DPFE circuitry, or your PCM is bad. You might try testing the DPFE and VREF signals for shorts-to-ground.

 

I just read that you have replaced it... buy the new revision, Ford Motorcraft part from a dealer, I'll bet you problem will go away. Also, check the hoses that connect to the DPFE, make sure they are not plugged and that they don't have holes in them... if the hoses or the metal pipes they connect to or plugged, the problem won't go away.. you will need to use high-temp hose (from teh dealer) to replace worn ones.

I know there was a "warranty extension" offered recently on many makes of Ford / Mercury products, having to do with the old-style DPFE sensor... It's a relatively cheap part (the one for my 2002, which did go bad about 2 months before Ford offered the warranty extension, was only about 30.00 or so) and easy to change... I too, had a 1400 code and one other one.. EGR, I think, but they all pointed to the DPFE sensor, according to the TSB I read.

 

BTW, just checked the TSB (I have a subscription to alldata).. your Ranger definitely falls under the recall, and DTC1400 is indeed one of the errors possible with the defective unit. Get a Ford Motorcraft unit.. BTW, if it has under 60,000 miles, it's a free repair at the dealer.

 

What is the TSB #?

 

Thanks for all the help. Unlucky for me, the truck has 62K miles on it, so free repair is out. I would rather do it anyway, less complicated than scheduling an appt, going to the dealer, etc. Would the cost of the part still free??? $50 is $50.Bryan

 

95% of the time when a ford dpfe goes bad, it sets a P0401, not a P1400.

Sometimes the hoses deteriorate internally, and little pieces of it gets pushed up into the sensor itself and damages it, although I'm not sure it'd set a P1400

 

From everything I have read about the P1400, it is a defective DPFE sensor almost 100% of the time. My problem is that something is causing them to go bad prematurely.

Rock - the diagram you provided doesn't look exactly like (but very close) the plug on the DPFE sensor on the 01 4.0, but I check all 3 pins for a short to ground with an Ohm meter. The right and center pins (signal and return) both are 100% ground, while the left (VREF) is about %50. When I unhook the wiring harness from the PCM, it all goes to 0%. That tells me "short" isn't in the harness, but is coming from within the PCM. This was done with the key off. Does this tell me the PCM is bad or is this the correct behavior of the PCM with the key off??????????? How do I verify?

Bryan