2021 Honda Pilot – Battery suddenly dropped to ~2V after driving
 

Hi everyone,

I experienced a strange electrical issue with my 2021 Honda Pilot and I'm trying to understand what might have happened.

Battery:
AGM Energizer battery from Costco (manufactured 2024/2025)

What happened:

· I drove the car for about 20 minutes.

· Shortly after parking, someone near the car noticed the left/right turn signals flickering on and off, almost like the vehicle was trying to start electronics with a very weak battery.

· About 10 minutes later, I arrived and checked the battery with a voltmeter.

Voltage readings:

· Initial measurement: ~2V

· Over the next few minutes, the voltage slowly climbed back toward ~12V

· After about 5 minutes, the car was able to start normally

After starting the car:

· After ~2 km drive + 5 minutes idling, engine off battery voltage: ~12.8V

· With engine running: ~14.8V

So the alternator appears to be charging normally.

Questions:

1. Has anyone seen a Honda battery drop to something like 2V and then recover?

2. Could this be caused by a loose battery terminal, ground issue, or BCM/module staying awake?

3. Are there any known electrical issues on the 2021 Pilot (multiplex/BCM, brake booster wake-ups, Auto Idle Stop, etc.) that could cause flickering lights and a sudden battery collapse?

The battery itself is relatively new, so I’m trying to determine whether this is more likely a connection issue, battery defect, or vehicle electronics problem.

Any ideas or similar experiences would be appreciated.