As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOTICED A PUNGENT SUFFER ODOR IN THE COCKPIT WHILE AT FL410 IN CRUISE POWER, ODOR SEEMS TO COME AND GO. ACCOMPLISHED AN EMERGENCY DESCENT AND LANDING W/O FURTHER INCIDENT. FOUND COCKPIT ACM VERY STIFF TO TURN. REPLACED ACM IAW 750 MAINTENANCE MANUAL CHPT 21-51-00.