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Gallagher99, Senior Vehicle Technician
Category: Ford
Satisfied Customers: 3333
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Hi, I have a intermitant fault on my ford Mondeo titanium X,

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Hi, I have a intermitant fault on my ford Mondeo titanium X, automatic gear box, reg EF10 YWC. It has a problem when starting, but only happens maybe once a week. It is push button start & when you get into the car & try to start it as normal, everything come on, radio, dash display etc but the engine wont start. I have checked the battery voltage & it is 12.5/7 volts when idle & goes up to about 14V when the car is running. Sometimes after trying to start it quite a few times it will just start & other times the only way I can get the car going is by jump starting it, which works everytime. An auto electrician has done a diagnostic on the car but it says there are no faults.
Any thoughts/help would be appreciated.
***** *****
Hi there doug good afternoon to you
Ok just to confirm the fault
Intermitently you press the start button with the clutch pedal down but the vehicle doesent crank but all the ignition lights etc come on
Regards Brian
Customer: replied 3 years ago.

Hi Brian,

Yes, but it's the brake I have to press not the clutch on this model. all the start up lights apear as normal, radio comes etc

Hi there doug thanks
Ok as the ignition lights emetic come on As normal this rules out a keyless system issue
Am just going to look through the automatic starting system and get back to you as this differs from the normal clutch pedal operating system
Thanks for you pateince
Customer: replied 3 years ago.

No problem, thanks

Hi doug do you have your registration number there as there is again a few Varients depending on exact setup
Thanks Brian
Customer: replied 3 years ago.

it is EF10 YWC

graphic Hi doug thanks

ok as this issue is of an intermitent nature it makes it a bit more difficult to diagnose as you will understand and this system contins severaL components and is very technical and complex
we can rule out a /immobilsor issue as the ignition switches on thus the keyless module reads the key the only other thing that can inhibit the start comand is the brake pedal switch which i suspect is ok as we havent had any issues with this switch

ok the starter motor is engaged through the strarter relay R1 in the engine bay fuse box
the pcm sends a feed and an earth to pins 1& 2 at the same time to engergise the relay
and send power out of pin 5 to the starter motor it also receives a command from the keyless module as a backup
ideally this should be checked with the fault present ( which is very difficult as its intermitent

having looked through the wiring diagrams and my technical notes i keep through the years and suspect the issue may be down to a faulty starter relay
there was an issue a few years back doug whereby a few relays were affected (the cause was the relay iternals being contaminated by lubricant used in production
and is an issue i have seen several times

the fix was to install 4 new modified relaysthe part number of the kit is(###) ###-#### ***** petrol -2.0 ecoboost)

as the fault is intermitent we must rule out the possiblity of this relay R1 causing our issue
here is a picture of the fuse box with the affected relays shown


if you need anymore help or advice on this issue doug please let me know and i wil do my upmost to assist you as i can understand how frustrtaing these intermitent issues are
if you have been completely satisfied with my answer/advice
kind regards ***** ***** and have a nice day

Customer: replied 3 years ago.

Hi Brian, Thank you for your answer. You are the only person who has been able to offer a concise detailed answer to the probable cause of this fault. I will give the relays a try & fingers crossed will solve it!

Kind regards,


No worries doug as I says intermitent faults can be a real pain sometimes this we use a process of elimination to try and resolve the issue
If you need anymore help or advice on this issue doug please let me know
If you are completley satisfied with my answer /advice
We can continue in this post even after rating the answer /advice
Kind regards ***** ***** and have a nice day
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