The receipt notice you should have received after your I-821D application was filed with U.S. Citizenship and Immigration Services (USCIS) will have a receipt number in one of fields near the top of the page. It will begin with three letters, followed by ten numbers. The receipt number will also appear at the top of the biometrics appointment notice. You can use that number to check on the status of your case at USCIS.gov. On the USCIS.gov homepage, click on the button marked "Tools," then click on "Check your case status online." Enter the receipt number and you can find out whether the case is still pending or if some other action has been taken in the case.
You can also sign up for automatic updates by creating a USCIS.gov account. On the Case Status Online page, scroll down and click on the "Sign up" button.
You can check the standard case processing time for this type of application by clicking on the "Tools" button on the USCIS.gov main page, then clicking "See office case processing times." For my clients, the I-821D DACA applications are typically processed at the Nebraska Service Center, so you can check processing times for that Service Center by selecting that option near the bottom of the "USCIS Processing Time Information" web page.
If your DACA expires before the renewal is granted, you will not be work authorized during any gap period. You will also begin to accrue unlawful presence. If you are facing that issue, check with a reliable immigration attorney to see how this might affect your individual case. You will not lose your DACA permanently if your current period of DACA expires while your renewal application is pending, as long as your renewal application is approved. You can file a renewal application even after your initial grant of DACA expires, for up to one year after the expiration date. After that time, you must file a new initial application. Check the USCIS DACA FAQ for more detailed and up to date information