2011 XC70 Overnight dead battery with no Alarm Module

davewave365 · Post by **davewave365** » 15 Jul 2024, 15:40

I have a 2011 XC 70 that randomly goes dead overnight. I found it once with the flashers on, so I assumed it was a bad siren module. I pulled the module from the wheel well. It still randomly goes dead.

Strangely when I hooked it up to the charger, the horn started blowing, which I assume was caused by the door being opened to pop the hood. I assumed the alarm would be inop due to the missing siren.

I don't need an alarm.

Any ideas what the issue might be?

Thanks!

AVOIT17 · Post by **AVOIT17** » 16 Jul 2024, 07:10

This has happened to me as well 3 times with an 2009 XC90 and once with a 2011 XC70.

Since these events are unusual/intermittent they are very difficult to diagnose if not impossible.

If this happens regularly you may want to measure the 'parasitic draw' on your battery to see if it is beyond normal. If it is, then there is a method to determine the source of the unwanted drain.

Google on YouTube "Parasitic Draw"

davewave365 · Post by **davewave365** » 16 Jul 2024, 12:24

Found it. Sirrus XM stuck on update. Known issue, there is a TSB/lawsuit in the works. Pulled the power plug and installed shunt so the radio still works. Volvo part # 8688083.