For a couple of weeks now, I have heard some seemingly random bleeps that eminate from our '05 Rav4. Recently, I heard 4 beeps when the car was unlocked and the passenger door was open but I don't think any key was in the ignition. This morning, a couple of single beeps were heard when driving along. I've checked the handbook, but can't immediately see anything that might explain them. Any ideas out there in Rav-land? Also, is there any way of seeing diagnostic codes via the radio display? Does anyone have the sequence to get them displayed, and their meaning?