Cadillac Lyriq Parasitic Draw: Why Your EV Dies Overnight

Why Your Lyriq Battery Drains Overnight

In your Cadillac Lyriq, the 12-volt battery runs the computers, infotainment, locks, and lights. When the car is off, those systems should go to sleep and draw only a tiny amount of current—usually under 50 milliamps. A parasitic draw means something is staying awake and sipping power all night. Common culprits include aftermarket dashcams or radar detectors plugged into an always-on USB port, a key fob left inside the cabin, a door or liftgate that isn't fully latched, or a module like OnStar or the infotainment system that refuses to sleep because of a software glitch. Even a weak or failing 12V battery can drain itself internally.

What to Check First

• Test the 12V battery with a load tester or voltage check. A battery that drops below 12.4 volts overnight may be the problem itself.
• Remove aftermarket accessories from USB ports and the OBD-II port. These are notorious for keeping modules awake.
• Check all doors, hood, and liftgate for ajar switches that might not be reporting correctly.
• Measure parasitic draw with a clamp meter or multimeter. After the car sleeps, anything over 50 mA is suspect. Pull fuses one by one to isolate the circuit—infotainment, telematics, and body control modules are frequent offenders.
• Look for software updates from Cadillac. Many parasitic draw issues on the Lyriq are fixed with a dealer reprogramming.

Is it safe to drive? If your Lyriq starts and drives normally, you can drive it, but you risk being stranded if the battery dies again. If you see multiple warning lights, reduced power, or the high-voltage battery also draining, park it and call your dealer. A repeated overnight drain can damage the 12V battery, so don't ignore it.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.