Yesterday, the SES light went on right after engine started. The car seemed to behave normally. It's a 2005 MO with 15.5k mi. I hooked it up to the OBD and the error codes are P1121 and P2135. The FSM says errors are cause by throttle actuator and throttle sensor, respectively. My guess is that the on-board computer sends the command to open the throttle by a certain amount but the sensor feedback indicates a different amount, and the discrepancy caused the error code. I reset it today and it hasn't come back after a few starts and a short drive. I certainly hope this is just a glitch and not a true defect. Quickly looking through the service bulletin didn't find anything relevant. Any ideas?