Hey all,

More au fait with my Focus than my parents Fiesta. It tends to go flat, but i'm more inclined to believe this is down to the fact that it is no longer driven daily, sometimes as much as a week between journeys, and if journeys are done they are extremely short (<5 mins) with doors/tailgate potentially open for some time.

Read the DTCs after the last episode, a bunch of U codes (not unexpected), and a sensor fault (steering position sensor), but nothing else. The car is charging at 13.4V when running which seems a bit low compared to the 14.2V of my Focus. I cannot unfortunately get to the alternator to unplug the multiplug to see if it changes voltage or anything when I do so - fat hands and fingers! I've also looked for any OBD/Forscan data to indicate charging voltage / desired charging voltage but there are none - making me think that this charging system is "dumb" as it were.

Battery replaced within the past 2-3 years.

Anyone know the charging voltage of a Fiesta of this age?

I don't know the answer re voltage but i would have thought it should be over 14. 

My brother's Focus 1.8tdci had low charging voltage causing flat battery. Breakdown man had a look at said the alternator needs replacing. But on further investigation (when I was starting to fit a 2nd hand hand replacement alternator) I found that the fault was the alternator pulley. the pulley was a type with a one way clutch in it. That clutch had failed so the pulley was only turning the alternator at a much slower speed than the pulley speed. Something had happened inside the pulley and loads of iron filings, metal dust was falling out of it once off the car.  Fine after new pulley fitted. 

I do not know if that fiesta might have such a pulley. 

1 hour ago, isetta said:

I don't know the answer re voltage but i would have thought it should be over 14. 

My brother's Focus 1.8tdci had low charging voltage causing flat battery. Breakdown man had a look at said the alternator needs replacing. But on further investigation (when I was starting to fit a 2nd hand hand replacement alternator) I found that the fault was the alternator pulley. the pulley was a type with a one way clutch in it. That clutch had failed so the pulley was only turning the alternator at a much slower speed than the pulley speed. Something had happened inside the pulley and loads of iron filings, metal dust was falling out of it once off the car.  Fine after new pulley fitted. 

I do not know if that fiesta might have such a pulley. 

Looks ok, battery test result was "Replace", Euro car parts unfortunately isn't open so we've charged it and will ensure the car runs at least once a day until we can replace it under warranty.