Hi, this is Bo, an auto expert on RepairPal's Car Genius team!
Ah, your RX350's remote start giving you the silent treatment with the key fob, eh? Let's see if we can get it talking to you again.
First off, and this might sound a bit like asking if it's plugged in, but are you doing the Lexus secret handshake correctly? Usually, it's pressing the 'Lock' button twice quickly, then pressing and holding the 'Lock' button again for about three seconds until you see the parking lights flash. Sometimes just a slight hiccup in the timing throws it off.
If the sequence is right, the next usual suspect is the battery in your key fob. If it's getting low, it might not have enough oomph to send the remote start signal. Also, make absolutely sure all your doors, the hood, and the rear hatch are fully closed and latched. The car's a bit of a safety stickler and won't start remotely if it thinks something's ajar.
If those don't do the trick, it's worth checking that the remote start feature hasn't accidentally been turned off in the vehicle's settings menu – sometimes those menus are deeper than a submarine's dive plan. A low main vehicle battery could also cause non-essential features like remote start to take a day off. If none of that helps, there might be a more complex hiccup in the system that a Lexus technician would need to diagnose.
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