Weird (to me) 2.0 Diesel S-Max Intermittent Fault
Discussion
Trust me to say it was the most reliable car I'd ever owned...
I've got a 2010 2.0 Diesel S-Max (140) with 100K miles. I've asked on Ford specific forums and there's been some helpful suggestions but no progress so far.
It periodically cuts out (about once a day on average but, really, randomly - no pattern I can work out).
If the car's moving, it restarts immediately - oil pressure light flashes (to be expected I guess) and usually the traction control light comes on and stays on (not always though). If it's stationary, it obviously doesn't restart. Lots of fault codes from ABS module saying they've lost contact with other modules (and most of those modules say the same). The only other maybe-relevant code is from the PCM - power relay de-energized too early.
Today it went into limp mode - turbocharger under-pressure. Ten mins after parking up, it started and ran fine - all I'd done was check the MAF sensor was plugged in properly.
It's off to my usually-reliable independent tomorrow (again - they've seen it a couple of times and fixed an earth and changed the battery, which to be fair did need doing). I trust them, but they are struggling with this and any steer or suggestion I can give them would be helpful to avoid some long-drawn-out replace-bits-til-it's-fixed-fest on a pretty old car (particularly if it ends up at the dealers).
(It started with it periodically refusing to start with an 'immobiliser active' fault - this turns out to be a well-known thing to do with the ABS unit, and clearing the fault codes fixes it, at least temporarily. That seems to have been fixed by cleaning up the corroded earth (not recurred for a couple of weeks) - this together with all the ABS loss-of-contact errors made us think it was something to do with that - but with the limp mode thing I'm not so sure, or even if these things are related or just a coincidence.)
Apologies, got a bit long:-( Thanks in advance for *any* ideas.
I've got a 2010 2.0 Diesel S-Max (140) with 100K miles. I've asked on Ford specific forums and there's been some helpful suggestions but no progress so far.
It periodically cuts out (about once a day on average but, really, randomly - no pattern I can work out).
If the car's moving, it restarts immediately - oil pressure light flashes (to be expected I guess) and usually the traction control light comes on and stays on (not always though). If it's stationary, it obviously doesn't restart. Lots of fault codes from ABS module saying they've lost contact with other modules (and most of those modules say the same). The only other maybe-relevant code is from the PCM - power relay de-energized too early.
Today it went into limp mode - turbocharger under-pressure. Ten mins after parking up, it started and ran fine - all I'd done was check the MAF sensor was plugged in properly.
It's off to my usually-reliable independent tomorrow (again - they've seen it a couple of times and fixed an earth and changed the battery, which to be fair did need doing). I trust them, but they are struggling with this and any steer or suggestion I can give them would be helpful to avoid some long-drawn-out replace-bits-til-it's-fixed-fest on a pretty old car (particularly if it ends up at the dealers).
(It started with it periodically refusing to start with an 'immobiliser active' fault - this turns out to be a well-known thing to do with the ABS unit, and clearing the fault codes fixes it, at least temporarily. That seems to have been fixed by cleaning up the corroded earth (not recurred for a couple of weeks) - this together with all the ABS loss-of-contact errors made us think it was something to do with that - but with the limp mode thing I'm not so sure, or even if these things are related or just a coincidence.)
Apologies, got a bit long:-( Thanks in advance for *any* ideas.
Really it could be any number of wiring issues...the fact multiple modules are involved could suggest a CAN issue, where modules are failing to talk to each other correctly.
Not an easy thing to trace, and it doesnt take much damage to the wires, corrosion or whatever to cause comms problems.
It could also be a ground, or even batter issue...but sounds more problematic than that and not something the average mechanic will easily be able to trace and sort. ( and that assumes even an actual competent average mechanic which is rare, nevermind someone capable of diagnosing this one )
Not an easy thing to trace, and it doesnt take much damage to the wires, corrosion or whatever to cause comms problems.
It could also be a ground, or even batter issue...but sounds more problematic than that and not something the average mechanic will easily be able to trace and sort. ( and that assumes even an actual competent average mechanic which is rare, nevermind someone capable of diagnosing this one )
stevieturbo said:
Really it could be any number of wiring issues...the fact multiple modules are involved could suggest a CAN issue, where modules are failing to talk to each other correctly.
Not an easy thing to trace, and it doesnt take much damage to the wires, corrosion or whatever to cause comms problems.
It could also be a ground, or even batter issue...but sounds more problematic than that and not something the average mechanic will easily be able to trace and sort. ( and that assumes even an actual competent average mechanic which is rare, nevermind someone capable of diagnosing this one )
:-( why I mentioned the dealer as that's the last resort in the hope there's some collective knowledge (there's a bulletin for something similar affecting the body control module, but it's clearly not exactly the same as this though). But thanks, appreciate you reading and responding.Not an easy thing to trace, and it doesnt take much damage to the wires, corrosion or whatever to cause comms problems.
It could also be a ground, or even batter issue...but sounds more problematic than that and not something the average mechanic will easily be able to trace and sort. ( and that assumes even an actual competent average mechanic which is rare, nevermind someone capable of diagnosing this one )
I have a 2010 S-max TDCI and had exactly the same symptoms. I was under the impression that the cam belt had been changed when I bought the car. Needless to say it hadn't.... The associated wear in the belt allowed the timing between the cam and crank to get out of accepted tolerances, which causes the engine to shutdown (I can't recall the fault code). New cam belt & tensioner fitted, and a new crank sensor and no more problems!
NervousEnergy said:
They've just called me and told me there are NO codes stored - like hell there aren't! I downloaded them this morning and sent them the list, and there's permanently one with the reversing lights because I re-wired them with a relay (£500 otherwise). Dealer tomorrow then:-(
Perhaps they plugged their kit into the 12v socket instead of the OBD port 
NervousEnergy said:
:-( why I mentioned the dealer as that's the last resort in the hope there's some collective knowledge (there's a bulletin for something similar affecting the body control module, but it's clearly not exactly the same as this though). But thanks, appreciate you reading and responding.
A dealer would generally be the last resort anyway. Often they are the most expensive and most incompetent. Which is really a bad combination for the customer.stevieturbo said:
A dealer would generally be the last resort anyway. Often they are the most expensive and most incompetent. Which is really a bad combination for the customer.
Mine are definitely expensive (which is why I don't normally go) but they have proved competent in the past - it's worth a phone callSpoke to someone at the dealers who immediately said intermittently-faulty power relay in the BCM - which is reported by Forscan - would explain the cutting out. Also trivially easy to replace so worth a go. Not a 100%, and isn't clear it explains limp mode, but one step at at time.
Now I just need to work out which thing plugged in to the BCM is the power relay:-) beyond the fairly obvious guess. I'd get the dealer to do it since, fair's fair, they did tell me about it - except for the mandatory £100 'diagnostic fee'...
Now I just need to work out which thing plugged in to the BCM is the power relay:-) beyond the fairly obvious guess. I'd get the dealer to do it since, fair's fair, they did tell me about it - except for the mandatory £100 'diagnostic fee'...
With it being a non comms code I would have the dash clocks looked at.
Their is a know fault with the solder on the multiplug connection on the circuit board.
They used lead free solder and over time it cracks causing all sorts of cutting out,lights on dash,non start problems getting worse overtime
If your any good with a soldering iron it’s an easy fix you tube is your friend plenty of guides
Their is a know fault with the solder on the multiplug connection on the circuit board.
They used lead free solder and over time it cracks causing all sorts of cutting out,lights on dash,non start problems getting worse overtime
If your any good with a soldering iron it’s an easy fix you tube is your friend plenty of guides
For the sake of an hour or so it’ll be worth a bash.
It’s a pretty common thing on most of the ford range of around that age.
Happened to a mates focus even slamming the door or a bump in the road would make it cut out and dash light up like a Christmas tree much fun was had getting that home.
Also check the ecu multiplugs in the passenger foot well they can get kicked and come loose.
intermittent faults are always the worst to find and fix
It’s a pretty common thing on most of the ford range of around that age.
Happened to a mates focus even slamming the door or a bump in the road would make it cut out and dash light up like a Christmas tree much fun was had getting that home.
Also check the ecu multiplugs in the passenger foot well they can get kicked and come loose.
intermittent faults are always the worst to find and fix
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