2008 1.8 TDCI losing power, rev counter dead and throttle input, crankshaft sensor?

[hcanning]

Hi guys,

I'm trying to diagnose an issue with a 2008 Focus 1.8TDCI.  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 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!

 

[manyfords]

Hi

If the crankshaft sensor  was failing am fairly sure the engine would not run. I have a 56 plate focus with the same engine. I disconnected my crankshaft sensor when I changed the oil last to see what would happen and it would not start. Connected it back up and it started again straight away. By the symptoms you are describing it sounds like it could be the instrument cluster failing with bad solder joints causing  various system communication problems. It might be worth having the instrument cluster sent of for testing. 

[hcanning]

11 hours ago, manyfords said:

Hi

If the crankshaft sensor  was failing am fairly sure the engine would not run. I have a 56 plate focus with the same engine. I disconnected my crankshaft sensor when I changed the oil last to see what would happen and it would not start. Connected it back up and it started again straight away. By the symptoms you are describing it sounds like it could be the instrument cluster failing with bad solder joints causing  various system communication problems. It might be worth having the instrument cluster sent of for testing. 

 

Thanks for your reply.  You were actually spot on.  I did some further diagnosis and testing and determined the IC was at fault. A new (second hand) one is in, thanks to the amazing wonderment that is FORScan, and all is well.  Thanks!