May be associated with other errors, such as "Check Engine" light, ICS / backup system warning, etc.
Simple fixes that may save you time/money:
1. Check gas cap is tight.
Yes, it's stupid - damn stupid, in fact. But it worked for me and others.
Note the old RX330s had a similar issue, in that it would throw error codes if the gas cap was loose. Happened to me a few time when the weather got really cold. It's all because the car is looking for leaks in the emissions control system and sees that the pressure in the gas tank is not holding steady.
2. If codes do not clear themselves, disconnect battery for 5 min, then reconnect and start.
• Open the door during that 5+ min, to ensure system is fully discharged. Not needed but can't hurt.
• Yellow ICS light (top right-hand corner on RX350) will flash on restart. It will self-reset upon driving, don't worry about it.
3. Recharge battery to full, then retry. Worked for him and others.
It seems a near-dead or weak battery will cause the car to puke lots of codes. If this is your issue, consider replacing your battery, as it's likely on its way out.
I recommend disconnecting the battery while recharging so you can get the benefits of (2) and (3) in one go. Not necessarily required, though.
Some people say this occurs when the gas is low / very low., even to the point of claiming you're risking damage to your fuel pump.
I call BS on this since automakers know people will run their car down past reserve, and a few people will inevitably run out of gas, and the car / fuel pump has to tolerate this gracefully. Honestly, how stupid do you have to be to make a fuel pump system that will be damaged if you run low on gas?
Regardless, you can try filling up (and making sure your gas cap is TIGHT).