When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The spare key could be flat too...they usually activate/wake up when they sense movement, so if the key is always being jiggled around (say in a pocket) the battery will drain quicker.
Got to admit last time I saw that was on a CR-V and that did say in text to change remote battery. It’s the same symbol though.
If the car opens and starts normally I can’t think what else it could be; The symbol for no key/key error is different.