I had the same lights come on my Lexus RX 300 and after searching some forums I ran across one guy who mentioned it happened to his 4 runner after service. He said he found that the air hose setting directly behind the air filter was disconnected.
I recently had my Lexus serviced and after disconnecting the battery on two different occassions, I went out side took my flashlight and looked down behind the air filter and sure enough there was the hose disconnected.
Most of the time it happens when service or the air filter has been checked and the hose comes off. I reconnected the hose, disconnet the battery and the light hasn't come back on. On the forum I read about it, the guy mention that it takes about 100 to 200 miles after it is disconnected before it comes trips the lights. I thought at first it was my gas cap, I retightened the cap and disconnected the battery and the light stayed out for about 4-5 days, it found the hose off behind the air filter and put it back on reset the code by disconneting the battery and it has stayed off.