Freelander 2 rear brake pads

Hi, I am new to the Freelander having been over on the Series site for many years. I have a Freelander 2 and my Daughter also has one.
2013 model year Freelander 2 with electric parking brake.
I have fitted new rear brake pads unaware of any need to get the vehicle into a service mode before winding pistons back. The car started and ran fine for a couple of days but has since put up a few warning messages and now will not start. I will go to my Daughters tomorrow to read any message/fault code, meanwhile any ideas of what I have done and any way out of it ?

Is there a warning on the dash before/during/after starting? Did you do any other work like changing the fuel filter?

Hippo, thanks for the reply. I checked the battery voltage and it was down to 8 volts. Charged up and started OK and alternator is charging so new battery fitted. All sorted now, I thought it was something to do with my messing around with the brakes and didn't think about other symptoms.