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CarDoc
CarDoc, Auto Mechanic
Category: Ford
Satisfied Customers: 361
Experience:  IMI L3 Motor Vehicle Mechanic
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My son has recently bought an S Max. 2014 titanium model. It

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My son has recently bought an S Max. 2014 titanium model. It was fine at first but has cut out a couple of times. He took it to a diesel specialist who could not find anything wrong
JA: How old is the engine? And when was it last serviced?
Customer: Well as i said it is a 2014 model. and the service book appears to be up to date. He bought it at a ford dealership so presumably they would have serviced it prior to sale
JA: What is the model of your '14 Ford?
Customer: It is the S Max titanium 2.0 litre diesel
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: No This is my sons car that he has just bought in the last three weeks. He called out the AA . He also took it back to Ford who could not find fault, He then took it to a diesel specialist
JA: Anything else you want the Mechanic to know before I connect you?
Customer: no

Thank you for using JA. I'm Baz, one of the automotive experts, I try to be available in the afternoon on weekdays and in the evenings on the weekend. I apologise if I do not respond to your question promptly, I can assure you that I will respond as soon as I can. Thank you

Customer: replied 10 days ago.
That is fine

I would like to ask a few questions:

Did the dealer scan the car for fault codes? Do you get any warnings on the dashboard just before the engine turns off? Does it happen on a cold engine or warm engine?

Customer: replied 10 days ago.
As far as i am aware it happens with a hot engine. The diesel specialist said that he could not fault the engine. he said that there were a couple of ECU messages that related to crank shaft but decided that they were due to dirty sensors
Customer: replied 10 days ago.
It is an S Max Titanium TDCI-138 A
Customer: replied 10 days ago.
Are you still with me ?

I was going to mention the cam and crank sensor faults in my next question. I would suggest getting the crank sensor replaced first, these sensors are major engine sensors and even if they are dirty, they will cause the engine to turn off, here's how:

The ECU obviously doesn't physically know the position of the engine, it uses the cam+crank position sensors to know this, if these sensors give wrong feedback to the ECU, the engine will shut down.

Customer: replied 10 days ago.
Why would it simply completely shut down the engine ? Isn't that really dangerous ?
Customer: replied 10 days ago.
Is changing the crank sensor a big job ?
Customer: replied 10 days ago.
Are you still there ?

The ECU won't know the position of the pistons and valves because the ECU determines these positions from the cam+crank sensors so, it will affect the fuel injection timing as well.

These sensors aren't the only reason that the engine will shut down, a problem with fuel delivery can also cause this.

Customer: replied 10 days ago.
Ok Thanks for the advice

It's usually not a big job, it depends whether the crank sensor is buried deep in the engine bay or not.

Customer: replied 10 days ago.
Thanks.

Follow this GUIDE which I found online.

Hope this helps

Customer: replied 10 days ago.
You Didn't say why the engine would shut down putting the occupants in danger

If the ECU doesn't know the position of the pistons, the timing of the fuel injection will be affected and the engine will die.

Customer: replied 10 days ago.
seems dangerous. i lose power steering and braking if my engine did just stop

You have to remember that the sensors are converting the physical position of the engine piston and valve into electronic signal so the ECU can use this to inject fuel at the right time to keep the engine running.

It is dangerous for the engine to die randomly and this issue needs to be resolved ASAP really.

Customer: replied 10 days ago.
Thanks for the advice

Welcome :) All the best and thank you for using JA!

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