My Fiesta Ghia 5 door 2007 is suffering from fault u0120

[Oberks]

In other words my battery warning light keeps coming on and often staying on. As far as I know this fault comes under code u0120 and refers to a failure to communicate between the ECU and the alternator !

This has been going on for several weeks now but the battery is definitely charging and the car is performing normally. I had a garage check the battery and alternator and they reported that the alternator was working normally and the battery was fine. I have three questions which I am hoping someone can answer!

1/ What long-term problems may occur if I continue driving when the battery light on comes on?
2/ Will re-setting the ECU solve the problem?
3/ Can re-setting the ECU cause other problems and failures?

Thank you for any help anyone is able to give me.

[E-bmw]

Has the battery recently been replaced?

[51mes]

Isn't this now an MOT fail if the battery warning light comes on and then stays on?

One possible fault as indicated above is that a new battery has been fitted, and it needs coding to the car..

One thing to try is disconnect battery leave it for 20 mins and reconnect.

S.

[Oberks]

E-bmw said:

Has the battery recently been replaced?

Thank you for answering, no, the battery was replaced about a year ago but the trouble didn't exist until a few weeks ago! Any further suggestions would be
welcomed.

Thanks

[Oberks]

quote/
One possible fault as indicated above is that a new battery has been fitted, and it needs coding to the car..

One thing to try is disconnect battery leave it for 20 mins and reconnect.

S.
[/quote]

No the battery was replaced about a year ago but the problem has only existed for a few weeks. It was raining yesterday so I didn't didn't disconnect the battery then.

I am just about to go outside and try it now (and wait for 20 minutes) I will let you know if it works, probably in a day or two so I can drive the car around for a while.

Thanks for replying to