I was told by a dealer service manager to disconnect the battery cable if the car was going to be unused for two weeks to avoid the battery draining. I am concerned they just didn’t want to check for a drain.
Why should they check for a drain? You haven’t mentioned any problems.
Two weeks is not long enough to drain a healthy battery in a healthy car. Still, not everyone’s car will pass such a test. Therefore it may be a sound idea to disconnect the battery before your trip.
If you are indeed having known problems with a discharged battery, provide the details.
To clarify, the dealer is probably talking about the conventional 12-volt battery, not the hybrid battery pack. Modern cars, especially one with as much fancy stuff as your Highlander, have a lot of electronic devices that draw a little bit of current even when the ignition is off. It’s nowhere near enough to drain the battery during typical use, but if you’re letting the car sit for a while it will eventually drain the battery and leaving the battery discharged for a long period of time can damage it. This is true of any car, hybrid or not.
That said, I think it’s a little overkill for two weeks. If it was two months I’d say definitely do it, but over two weeks, it probably won’t even drain, let alone damage the battery.
If the Highlander is like the Prius then yes, you should disconnect the auxiliary battery if not used in 2 weeks or more. The Prius aux battery is a small sealed lead acid battery. It’s smaller than a regular car battery because it normally does not have to start the engine.
See page 8 of this link: