2008 Focus 1.8 TDCI losing power, no throttle, crank sensor?

[Howard-]

Hi guys,

I'm trying to diagnose an issue with a 2008 Focus 1.8TDCI (115ps). The problem is that after a while of driving, and at completely random intervals, the car will completely lose power among a bevy of dashboard warning lights and messages. When I drove it yesterday I managed to reproduce it - I lost all engine control - the rev counter went dead and the engine, whilst idling, wouldn't respond to any throttle inputs.

Looking in Forscan revealed a few fault codes (after initially resetting them all before driving) - e.g. to do with the instrument panel comms, BCM, and ABS module. One of the messages referred to a loss of engine speed data. I am assuming the other faults thrown up are as a result of the initial failure! But the engine speed warning would tie in with the fact that the rev counter was dead and the engine wouldn't rev above idle (possibly in a failsafe mode because there's no RPM input?)

So I'm thinking I'm going to change the crankshaft position sensor and see if it helps.

Has anyone changed one of these? Is it as simple as getting underneath and it’ll be easily accessible? I found one site that suggested you need to remove the alternator, but it seems to be mounted against the flywheel and the alternator is over on the other side of the engine...?



Hoping it’ll cure the issue but not particularly confident.



Thanks for any help!

[MajorMantra]

This might be a totally different problem, but on my Mk1 Focus 1.8TDCi the cutting-out problem seemed to be solved by replacing the cam sensor (not crank sensor) which was a very cheap fix. (£13 and no more than 10 minutes of my time.) Thread here:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

However there are a couple of key differences:

- the engine was cutting out, not just slowing to an idle
- no fault codes were stored