Any Car Mechanics?

ssc456

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Hi,

First off I know this is a long shot as this is not a car forum (derrr :?)
But I thought i'd give it a shot here first before registering with a car forum.

My Fiance's car is a little broken.

The diagnostic machine says there is a communication problem between the transponder and the ECU.

I've bought a replacement key, transponder, ignition barrel and ECU replaced them and the car still wont start.

Are there any other parts involved in letting the immobiliser know it's ok to let the car start?

The only thing I have left on my list is getting my volt meter out and chasing the wiring from ignition barrel to the ECU and seeing if there is a problem somewhere.


Just to be clear the symptoms is put the key in the ignition, turn it, all lights come on for second click, go to turn it over and nothing. Just silence. Fuel pump does sound like it's whirring into motion, checked starter motor, battery, relay and fuses. + the diagnostics machine says it's the ECU not talking to the transponder so i'm reluctant to look past this for the moment.

It's a Ford KA 1.3 Duratec engine on an 03 plate.
 
Hi,

First off I know this is a long shot as this is not a car forum (derrr :?)
But I thought i'd give it a shot here first before registering with a car forum.

My Fiance's car is a little broken.

The diagnostic machine says there is a communication problem between the transponder and the ECU.

I've bought a replacement key, transponder, ignition barrel and ECU replaced them and the car still wont start.

Are there any other parts involved in letting the immobiliser know it's ok to let the car start?

The only thing I have left on my list is getting my volt meter out and chasing the wiring from ignition barrel to the ECU and seeing if there is a problem somewhere.

Just to be clear the symptoms is put the key in the ignition, turn it, all lights come on for second click, go to turn it over and nothing. Just silence. Fuel pump does sound like it's whirring into motion, checked starter motor, battery, relay and fuses. + the diagnostics machine says it's the ECU not talking to the transponder so i'm reluctant to look past this for the moment.

It's a Ford KA 1.3 Duratec engine on an 03 plate.

Sorry :(. Small diesel car engines and all pickup truck engines is about my range, and very limited at that, but I will try. I'd say the ECU needs checked (duh)
 
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I hate computer cars. My 85 Camero was a PITA with its computer.
Until it was discovered where the wiring going to the computer through the firewall the rubber grommet was missing. The sharp edge of the hole was sawing through the cables insulation and shorting to ground. Which when it did the computer blew up. After the second time in less than a year I decided to replace the entire wiring harness. Scoping out how complicated it was going to be to replace it I came on to the missing grommet. $2.50 dollar part and it ran like the kitten it was for several years after.
 
Yeah well that's my thoughts.

I think I've got a long day with the voltmeter planned this Sunday.
 
Usually a car will have two electronic controls, Electronic Control Unit (ECU) & Body Control Module (BCM) in which these are usually programmed to work together so if you have replaced the ECU this could be the problem as it is not been programmed to work with the BCM.

It would be wise to pay a mechanic or your local car dealer to fix as they will have the appropiate equipment to do this.

Also a key transponder & Key will need to be programmed & you will need to source the correct instructions for your make & model of car.
 
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I think I'm ok without going to pay Ford £120 an hour thanks!
That's genuinely their hourly rate.
 
I'd start by putting all the old stuff back on.

the trouble is this:
the key needs to be coded with the transponder, and the transponder needs to be learned to the ECU, the ECU needs to be coded with the body.

Even if one of those parts was at fault, you won't know because they all need to be coded to each other.

so start by replacing everything and going back to square 1.
(which is where you break out the volt/ohm meter.)

there should be a coil (as in inductive coil) on the ignition barrel, check to make sure that there are no breaks in this. (if should unplug pretty much at the barrel)
then make sure that there are no breaks in the wire going from the ignition to the ECU.


the symptoms that you have, (lights come on but car won't start) sounds like an immobiliser problem, and it's a problem that I can replicate on my own car (though that's a Peugeot) simply by unplugging the inductive ring that surrounds the ignition barrel.
 
I think I'm ok without going to pay Ford £120 an hour thanks!
That's genuinely their hourly rate.
Wow £120 hourly rate, they sure rip you poor suckers off in the UK.

Any how back on topic just put your original ECU back in as Root suggested and see how things work for you, the problem was an error between ECU & Transponder with odds on transponder is probably the faulty part.
 
By ignition barrel do you mean the key lock? As you said that everything turns on, pump running tells me that the ignition switch is bad meaning it won't activate the starter. It's mounted on the steering column underneath the dash. the key lock is attached to it via a rod.

Also it can be out of adjustment (it slides) and can be readjusted.

And it's a common problem for failure to start the car.
 
Engine turns but doesn't fire? Does it do the exact same thing with a non-chipped key?
You can't just get a new chipped key, you also have to have it programed to match your car. And I don't think you can just replace the transponder without reflashing the ECU. You are going to have to take this to a dealer. Immobilizers can be a real pain. Heck, I'm an engineer at Ford and I can't tell you much else to help, haha.

As MMM said, the ECU and BCM need to communicate as well, and there might be an issue there.
 
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