C30 Key Battery Issue

I had a similar problem with my Volvo C30, though I can't recall the exact year. Same symptoms - keyless entry stopped working, and I was getting intermittent errors. It definitely sounds like the key fob battery. Have you tried replacing it yet?

Not yet, but I planned on doing it tomorrow. I was just curious if it definitely sounds like the battery, or could it be something more sinister? And, I have no clue what type of battery the key needs. I don't want to open it up until I have a replacement in hand. Do you know by any chance?

Based on your description and the error code, it almost certainly sounds like the battery. It's a very common issue. I'd still recommend a trip to the workshop to have them confirm and replace the battery, especially if you're unsure about the battery type. They can also clear the error code for you, which cost me 37€.

Thanks so much for the advice. I replaced the battery in my key, and now everything is working perfectly again. Keyless entry is back, and the error message is gone. I really appreciate the help.