Hi everyone, my first post so fingers crossed!
I want to replace the Crankshaft (speed) sensor on my Motorhome. It’s based on a Ducato 2.3L Multijet 130 2008 ( engine F1a). I’m getting random engine stalls and error code P0355 every time.
Question - where is the sensor located? I have a new replacement in hand and I have found a similar size and shaped sensor near to the timing belt side, tucked between the oil filter and AC pump. See picture, Is this the one?
It looks a sod to get to and doubting wether I can get a 10mm spanner/socket near it! Your help would be much appreciated, thanks

From quick research, there appears to be both a speed (rpm) sensor and a timing (tdc) sensor.

Not quite sure which you're trying to replace, (as I can't really relate either of these to the code) but these pictures should help.

My manual describes the crankshaft sensor as the inductive speed sensor depicted in HughJampton's first diagram. It also states that if the sensor is faulty, the rev counter on the instrument cluster will work erratically or not at all.

From looking at picture 1, provided by HughJampton, I learn that the ECU uses the crankshaft speed sensor determine the position of the crankshaft. The ECU also sychronises with reference to the camshaft sensor.

This would seem to be similar to the 2,8JTD ECU, where stroke information e.g. exhaust or compression is determined from reference to the camshaft sensor. Thereafter the ECU only uses the crankshaft (speed) sensor to control injection.

From the above, unless the 2.3 JTD control philosophy is different, it follows that a faulty camshaft sensor will cause difficulty when starting, while a faulty crankshaft sensor will cause erratic running, and as RS3100 has quoted erratic rpm indication.

Again for the 2.8JTD the sensor air gap is critical, 1mm being a typical value. The 2.3JTD could differ in this respect, but worth checking any possible adjustment when replacing either sensor.