As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PASS AND CREW COMPLAINT ABOUT EXHAUST FUMES NOTICED MORE DURING CRUISE AT 5000-7000 FT WITH HEAT ON. GROUND RAN ENGINES AT HIGH POWER SETTINGS. PERFORMED OPS CHECK OF TEMP CTRL SYS IAW AMM 21-60. RAN ACFT AT FULL HOT NO EXHAUST FUMES NOTED. OPS CHECK GOOD AT THIS TIME.