In order to check and clear troubles on the DSC PC1616, you will need to enter *2 on the keypad. At that point, a totally different number should show up. Once you get this number, please document it and refer to the trouble conditions which you can find below. 

Light 1 - Service Required - Press the 1 key for more info.

If the number 1 light stays on, it means the Main panel battery needs to be swapped out.

If 2 - will mean there is an open Bell Circuit,

If 3 - means General System Trouble (usually associated with Cellular/Internet Communicators),
If 4 - means General System Tamper (Open Tamper on an Expansion Board),

If 5 means Module Supervision (panel can't see enrolled keypad),

If 6 Means that a Wireless Jam has been detected,

If 7 means Expansion Board low battery,

If 8 means Expansion board A/C Failure.

Light 2 - Panel A/C (Power) Failure

Light 3 - Telephone Line trouble

Light 4 - Failure to communicate

Light 5 * - Zone Fault - Press 5 and then another light should light up. This represents what zone number is in fault.

Light 6 * - Zone Tamper - press 6 and whatever light appears is the zone that has the tamper.

Light 7 *  - Wireless Device Low Battery - Press 7 once to view Wireless Zones, Press 7 again to view Handheld Keypads, and press 7 again to view Wireless Keys. Once you figure out what zone 
it's coming from, all you should have to do is replace the battery.

DSC Powerseries PC1616 Frequently Asked Questions

DSC PowerSeries PC1616 Alarm Monitoring Options