Sienna start stop failure

Alright, gearheads, I'm pulling my hair out here. My 2020 Toyota Sienna hybrid is throwing a fit. The start-stop system is kaput at only 50423 km. I'm getting an error stored, the engine shuts off randomly (which is terrifying), and the warning light is mocking me from the dash. I suspect it's the battery, but has anyone else seen this gremlin?

4 comment(s)

I had similar symptoms on my Sienna. Is the automatic restart functioning, or are you getting stranded? It sounds like a discharged or defective auxiliary battery.

Stranded isn't the word for it! It's more like 'mildly inconvenienced with a side of panic'. Seriously though, the automatic restart is failing consistently. How did you fix yours? Was it definitely the battery?

Confirmed, it was the auxiliary battery. Given your description and the automatic restart failure, it's highly probable yours is the same. I'd advise getting it checked at a reputable workshop to be certain. It could prevent further damage to the hybrid system.

Thanks a bunch! Dropped it off at the shop, and you nailed it – the auxiliary battery was toast. New battery and 290€ later, it's purring like a kitten again. Appreciate the insight!

Join the discussion now: