Hi All, I bought a 2015 Focus Zetec 1.5 TDCi six weeks ago and have the following issue. When inspecting car prior to purchase, I noticed battery was 11.8v but car starting and driving very well with no electrical issues other than auto stop/start would only occasionally work. I thought I’d just buy a new battery as I was getting car for a good price anyway.

So, I got a battery of same spec and it was 12.6 before I installed it and 12.4 as reported by the Torque OBD app. When driving, the voltage stays within a range of 12.0 – 12.3 all the time and rises to 13.5 when deaccelerating. I know batteries should be around 14.2 when driving so it was suggested the alternator was bad and it did look very old.

So, I put new alternator in, but the voltage issues remain the same and no electrical related issues other than auto start/stop not working. After I installed new alternator, I now have a ‘engine service now’ notification appears every time when starting the car. No codes on my basic OBD scan tool and none reported by the garage’s high spec scan tool. Car is driving fine and not in limp mode but it’s driving me nuts not knowing what it is.

A mechanic suggested that the low voltage might be normal for Ford cars and their trickle charge system, but he couldn’t confirm if that was the case. Another thing I noticed is the dashboard auto stop/start icon is missing since installing new alternator, but icon was there beforehand. Any advice appreciated!

 

Some newer vehicles required the vehicle computer to be notified the battery has been replaced. Not sure about your model, but there is more these days to replacing a battery than days past. Check with your local dealership service dept.