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Gallagher99
Gallagher99, FORD SENIOR /SPECIALIST TECHNICIAN
Category: UK Ford
Satisfied Customers: 3154
Experience:  SVQ LEVEL 3, QAULIFIED FORD SENIOR/SPECIALIST TECHNICIAN , ATA REGISTERD ,12 YEARS EXPERIENCE
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Ford ka: i have a ford ka, 2003, engine mnt fuse blows when

This answer was rated:

i have a ford ka, 2003, engine mnt fuse blows when turn ign on, have disconnected every plug on engine, still blows, have cut yellow/purple wires at ecu, fuse now does not blow.

is there any common problem with these?
Hi there , good morning to you

Ok what is the exact fuse number that is blowing do I can have a look through the wiring diagram

Also if you can give me your registration number so I can clarify the exact setup
Regards Brian
Customer: replied 4 years ago.

Hi Brian


reg is mp03ekf, fuse number 20.


 


fuse blows as soon as ign turned on, as it stops blowing when I cut the yellow/purple wire to engine ecu, I would suspect the fault to lie eiher with the ecu or something it powers up (hence disconecting every plug from the engine!)


 


Martyn

Hi there Martyn


Ok let have a look through the diagram and get back to you in the next short while

Regards Brian
Hi there , ok I had a look through the diagram

Connect all wires etc back up And all Multiplugs
Then what to do is fit a bulb with a connector and 2 wires on it and fit the wires into where the fuse (this takes plsce of the fuse )would go and put the ignition on (the bulb will light up indicating a short circuit (feed and earth )

Now you need to start dissconnecting components till the light goes out this is the best way to trace a short circuit

Ok first off dissconnect The 4 injector Multiplugs and the idle speed control valve

Next dissconnect the vehicles speed sensor ,MAF sensor and canister (EVAP ) purge valve
Next dissconnect the fuel pump relay and the cooling fan relay
And monitor the light

Let me know how you get on and we can continue our diagnostics

Also do you have the chassis number as the reg number doesn't cOme up on my system
This is just to clarify this fuse doesn't power anything else

Regards Brian



Customer: replied 4 years ago.

chassis no:


wfobxxwprb2b13275


 


As I said, I have had all plugs disconnected from engine at the same time and the fuse is still shorted, I might add the starter does not engage, I assume this is the pats working as ecu is not powered?


MArtyn

Hi there Martyn

Ok have you removed the coing fan relay and fuel pump relay as well
Do you have the chassis number so I can double check this wiring diagram

Regards Brian
Customer: replied 4 years ago.

chassis no:


 


wfobxxwprb2b13275


 


Fan multirelay yes, fuel pump relay no, will try now.


 


ok fuel pump relay no change, but short goes if remove engine control relay, relay no 11.


 


martyn

Hi there
Martyn

Ok is relay 11 located just above the row of fuses in Thr passengers fuse box
And is 3rd along botXXXXX XXXXXne of relays

Our diagrams don't give them numbers only codes eg k45

Let me know and we can continue

Regards Brian
Customer: replied 4 years ago.

hi


Yes no 3, middle of 5 micro relays just above fuse's, autodata lists it as engine control relay.


 


Martyn

Hi there Martyn thanks for that

It lists The relay as fuel injection relay (this powers fuse 20 )

Ok as everything else has been ruled out them Thr PCM is the root cause of your short as fuse 20 powers the PCM at pin 37 (violet and yellow wire )

To clarify this again cut/seperate the wire at the PCM and turn the ignition on
If you have an earth coming up this wire (pcm side )then the PCM is shorting out internally

These older KA s were prone for water ingress into the PCM (this was seen by corrosion on the pins of the PCM )

If you need anymore help or advice on this issue martyn or any other please let me know
If you are completley satisfied with my answer /advice
PLEASE RATE MY ANSWER
Kind regards XXXXX XXXXX and have a nice day

Brian

Customer: replied 4 years ago.

Yes if I seperate the wires (2) from the ecu, they are both earth from the ecu , I did just lift lid off ecu, there is no sign of water damage or burn smell, but it is the same conclusion as I had come to, thanks.


 


 

Hi there Martyn

Yes this indicates the PCM has shorted internally
But it is better to clarify this as we did in our diagnostics
As you know power/earths can come through and from different sources do it is better to trace using the wiring diagrams

If you need anymore help or advice on this issue or sny future please Martyn let me know
If you are completley satisfied with my answer /advice
PLEASE RATE MY ANSWER
Kind regards XXXXX XXXXX and have a nice day

Brian
Gallagher99 and other UK Ford Specialists are ready to help you
Customer: replied 4 years ago.

Hi


Just to let you know, I have finaly got a s/h ecu and fitted it, car is all up and running now, thank you for you advise.


 


Martyn

Hi there Martyn
, good evening to you
Thanks for replying


That's good news that the vehicle is all sorted and running ok

If you ever need any future advice or assistance no matter how big or small you'd issue is please let me know

Kind regards in advance and have a nice evening

Brian