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Mike, Technician
Category: UK Ford
Satisfied Customers: 39198
Experience:  34 years experience of motor vehicle diagnostics
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How do I bypass immobiliser on 1999 ford mondeo diesel new

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How do I bypass immobiliser on 1999 ford mondeo diesel new pump fitted but the 3 black wires at back of diesel pump have been cut
Hello and Welcome to justanswer...

Is the pump you have fitted identical to the one that came off ?

Please give me Full info as to what is happening -

Rgds, MIKE....................................
Customer: replied 4 years ago.

the pump fitted is identical same numbers only the 3 black wires from the pump have all been cut.

I just need to bypass the immobiliser so the car will start not both about the car being immobiliser afterwards as car not really worth stealing


Customer: replied 4 years ago.

At the moment the car will not even turn over immobiliser stopping this

Hello again..

Thank you for your reply ..

You cant bypass the immobiliser Im afraid, its just not that simple, its all linked in with the engine management ecu - thats why the engine will not even crank... it cuts the starter as well as the fuel..

Why can you not see / tell where the wires re join ?

Rgds - MIKE......................................
Customer: replied 4 years ago.

The 3 black wires come out the back of the pump only about 1inch long each these need to be contected into the wiring harness . I have the harness and plug from the old pump but which order do the 3 wires contect

back together as there are 9 possible combination which I have already tried. If I do manage to get the right combination do I need to get the immobiliser reprogrammed

Hello again Paul...

My apologies for the delay - I have only just received your reply...

You will not need to code it normally - this pump has a simple fuel cut off so;lenoid ( normally under a 1/4 " thick steel cover...

You can supply that - I can tell you here that the wire that feeds that is from pin 45 on the Pcm... but any 12 v feed will activate it.

If you have it all together though - on switch on , the red LED should come on solid - then go off - and then you start the engine. If the LED flashes - it will flash a faults code sequence , which will tell you have a problem in the system..

Let me know how you are getting on -

KInd Rgds - MIKE.

Customer: replied 4 years ago.

Hi Mike


Thanks for info I will try this at the weekend and let you know Cheers Paul


Hi there Paul...

No problem - Im very pleased to have helped...

Again - if you need anything more yes,m by all means get back to me.. I'll carry on as needed / if needed, no problem..

.....................Please do click on the OK service rating, or higher for me now - as thats how Im credited for helping you - Thank You again for that..

NB - You can get back to me anytime you might need - Clicking the OK service rating does not close you out...

Kind Rgds - MIKE.
Mike and other UK Ford Specialists are ready to help you
Customer: replied 4 years ago.

Hi Mike,

The 3 wires that go into the back of the diesel pump I have tried ever combination the 3 black wires wires from the harness are

with ignition on one wire is live +

one wire is earth -

one wire nothing


the immobiliser light on dash by clock when ignition on just flashes constantly


Car will not turn over what ever combination I connect the wires in.


Any ideas Paul

Hello again Paul -

The live wire ( with ign on ) will go to the Stop solenoid- that the fuel cut off when you connect that to there -you should hear that click , allowing fuel through..

What you need to do with the immobilser side of things though - you need to switch the ign , the led should go out - if it doesn't watch it until the led settle down to a slow flash - it will flash a code.. ie, 3 flashes - then a gap.. then 1 flash... and so so. It can take a while for you to watch it and see exactly what "code" you are getting - Do that and let me know what you have.

Rgds - MIKE...................................
Customer: replied 4 years ago.

Hi Mike thanks for that I will try this as soon as I get chance (work gets in the way at the moment!) Paul

No problem at all...

All the best with it..

Customer: replied 4 years ago.

Hi Mike

At last got chance to try your advise the led flashes 3 then 2 then 3 then 2 etc

what ever combination I fit the 3 black wires Cheers Paul