Check Engine light on 323i

The check engine light has been on in my car for about 2 months now. I initially thought it was the gas cap, but my mechanic was able to pull a code from the car (the latest code is 1421). We've replaced the secondary air pump and value, the coolant thermostat, one of the oxygen sensors, and the mechanic cleaned out the fuel injector system. After about $1000 in repairs, still the check engine light is on - does anyone have any suggestions? This car has 95k miles on it, but has never had any major problems until now.

Hi Dana2003.
My engine light just appeared on my car today. It only has 17K miles on it. I will be visiting a BMW service center this week. Let me know if you find out the solution to reset the engine light.