Hi
I joined recently and I already found many helpful information in this forum.
Please forgive my english ( I live in France ) and tell me if my post is in the wrong section.

I have a ford fiesta 2007 tdci 1.6 (it is an mk6 according to my research in french it is labled Ghia VI). One week ago after I left it parket outside (very cold night and I got lazy to enter it) the car didn't started, the jump/pump start failed too. The battery is good, and everything works fine inside (dashboard, lights, ....) except the front windscreen heater (which I am not sure if it used to work without the engine running or not).
I plugged an elm327 and I read this fault code p1602 immobilizer/ecm communication error
I checked all the fuse in the passenger side and they all seem Ok.
No immobilizer warning when I try to start (It goes on for 3 second when I turn first position then off and never comes back again)
Any tips on the subject will be welcome.
Thanks in advance.

Hi

The heated windscreen doesn't work with the engine off as it draws a lot of current.

My first port of call would be to try an ECU reset - disconnect the battery for 24h and see if it works when you reconnect. Do you have any other keys to try it with? And thirdly, check the connections to the ECU and the dashboard display. I wonder if something has become disconnected.

Cheers
Nick

Thanks so much for your answer, I was busy last week and the car is far from my home. I went Friday and I disconnected the battery and left it the whole weekend, I tried yesterday but it's still the same. Yes me too I strongly think it is a connection issue somewhere due the humidity I bought an electronic spray for the ecu pins, if you can tell me where it is located to check it this evening.
Many thanks!!!

On the ST it's out in the open behind the passenger headlight/under the air intake piping. If yours is LHD that would be the drivers side headlamp.

Thanks will check that,
I took it to a local ford dealer and they refused to handle it, as it is so complicated and need expensive investigation time.

Hello,
I came back today to investigate the problem on this car, I checked some grounds and I wanted to check corrosion around ECU. After unmounted it I was surprised to find out that two pins are tied together (I will join a picture of it). Is it normal by design to have two ECU's pin joined together deliberately ? I know that the guy how changed the started unmounted the ECU so now I am not sure if he did it well or not.
Many thanks

I can not believe that those two pins are meant to be like that, can only guess that the plug has a bent socket and inturn that has forced the ECU pin over and bent it and I would think you would have serious error codes flashing up although it might just be enough to kill the whole car.
I could look at my old ECU but currently with a local tuner to see what data they can copy off it.
Nick will be along soon to confirm as I can't be certain.

Thanks so much for your answer.
Yes me too I think the same, but the way it is perfectly bend make me doubtful. Yes it will be great if you have the same ECU to check if some pins are joined together.
Do you have any idea where to find a diagram or a piece of paper explaining what each pin if for.
Thanks in advance.
ps : my ecu is bosh 6S61 - 12A650-VC 5DSC

I think the diagrams are knocking about on the internet, Nick above may know, I won't get my old one back for a while yet.

I've never removed my ECU plug, however I'd have an extremely hard time believing that the pins were designed to be like that.

If the feeds had to be joined, then from the factory they would be done in the loom itself rather than by the connector pins so my suspicion is no - that's not normal.

The bend looks perfect, but then its probably just that it was a little bent out of shape and the act of plugging the connector back in has bent it uniformly to force it into the hole next to it.

If I get a chance I'll unplug my ECU and see if it's the same, however - we can't take that as definite either as we don't have the same engine.