[rondeo]

DIY:

Measure the resistance of the element, (near 1.1 ohms), check fuse 6 and relay 4. Use a vacuum tester to see if there's a blockage in the vaporizer.

If all is good, check sensor hoses, replace or test the sensor (common problem I hear from Ford man but how to check it?).

?If no DIY and reluctant to see Dr Ford, don't worry unless fuel consumption and/or performance is noticed.

Probably not the DPF.

At least we have something to obsess about, since the engine is bulletproof?

Your regen interval seems high at that speed?

Cheers, armchair mechanic . . .