So after having my 2004 STR parked for about a month, I got back and was welcomed with warning lights and a message saying abs fault and dsc not available. Does anyone know what might of happened or how I can fix it?

 

Do some searches. This has come up before and is not always the same thing.

It might go away if you drive it abit and get everything working again. Cars don't like to sit unused.
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These modern jaguars do not like being left alone for such a time. You may find that the battery requires a full charge. Depending on how long the battery has been with the car, you may need a new one.
Cheapest fix, fully charge the battery and then keep an eye on it.
Top tip, if you do have to leave the car for standing for a long time, switch everything off in the car and then double lock it on the remote. This will basically put the car to sleep and drastically reduce the current drain on the battery.
Hope this helps.