Fault codes

At last my engine has been rebuilt and is back in the car,I have been to the garage this morning and the car is throwing up fault codes like windows sunroof traction control faults but they told me the battery is nackered and not holding a charge and it wont start until I go and press each window button and then the sunroof then the engine will turn, is this down to the battery been low and goosed, they orderd a new battery for me.cheers guys

Windows and Sunroof not set is the result of the battery being disconnected and all they need is to be fully opened then closed in turn to reset them....

Traction/ABS faults are usualy a weak battery....

Not sure why the engine will only start if you cycle the windows - but low volts will do strange things to a P38!

And if you missed a earth somewhere, sounds more like the cause, judging buy the work done, but the battery can be over its time as well, the window thing before you can start the engine says earth concern to me...........

I suspected the battery which is why im checking, but I will pass on the info bout a possible missed earth cable connection
Cheers chaps