As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LEVELING OFF AT FL 450, COCKPIT FILLED WITH HAZE AND A BURNED RUBBER ODOR, APU WAS OFF. IT QUICKLY DISIPATED AND NEVER RUTURNED. CABIN AREA WAS NORMAL. R & R THE COCKPIT TEMP CONTROL VALVE WITH AN O/H UNIT IAW MM 21-22-05. OPS AND LEAK CHECKED GOOD.