2013 Toyota Prius — hybrid fuel economy dropped with no warning light — Chicago owner

Ask what changed right before it started. Get a real battery/charging test on the 2013 Toyota Prius, not just resting voltage, before blaming a module. Save the big job until that test fails. Do that first. I refuse to clear codes until someone else sees them.

Checked the easy stuff on the 2013 Toyota Prius and found one clue worth chasing before I book a shop. Not driving it hard until I know more.

Start with the test that can prove you wrong. A pressure test beats staring at a dry driveway if the 2013 Toyota Prius is losing coolant with no puddle. If the cheap test changes it, stop and reassess. That's the whole play. Happens in gear, not in park, for what that's worth.

If it were in my driveway, if a shop can't duplicate it on the 2013 Toyota Prius, bring a video plus freeze-frame data, not just a story. Save the big job until that test fails. Learned this the expensive way on a previous car. I'd rather be boring and correct. Might be overthinking it, but I'd rather overthink than overspend.