DPFE sensor with CKP code?

Maintenance/Repairs
,
1

Hi again everybody. 96 Windstar 3.8 liter engine, 150000 miles.

3 weeks ago, I got a CEL light. Code P0340. Brought it my mechanic. He changed the CKP sensor. That didn’t work. Brought it back, he changed the spinning magnet under the sensor, (the thing that tells the computer that the crankshaft is in time, like the distributor used to do). That didn’t work. In the meantime, the van was running horribly. Idle would go from 800 to 400, like a miss, but not a miss. I found out the if I unplug the DPFE sensor, it runs like a top, no problems. CEL light doesn’t go out, of course. My mechanic has given up, saying it is the timing chain (NOT, otherwise it wouldn’t run well at all) or the PCM, (maybe). I tried changing the DPFE sensor, that didn’t work. This leaves a wiring problem or a PCM problem, (unlikely). Any Ford experts out there know if the CKP and the DPFE sensor wires meet anywhere in that spagetti mess under the hood?

2

Also, does anybody knwo the long term implications, besides have this yellow light stare at you in the face, of driving like this for an extended period of time?

3

I can’t comment on the wiring - you’d want to get a wiring diagram and look.

But I will ask this - you keep saying crank sensor when the P0340 is about the cam sensor. It is, furthermore about the cam sensor circuit - not the sensor itself. The circuit problem might be the sensor, but could also be elsewhere in the circuit. You and your mechanic both seem to be throwing parts at it. Codes don’t tell you to replace parts, and in this case it might even be the wrong parts.

So test the circuit for the cam sensor and the sensor itself.

I cannot comment on any connection between that and the EGR system - could be there is one, could be coincidental. And though it is true that Ford DPFE sensors commonly fail, they too are not the only part of the whole system. You have vacuum lines running to & from the DPFE - were those checked for blockage or breaks. There should be a solenoid in that system - was that checked? Then there is the EGR valve itself and its passages that can be checked.