As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 4000 FT, DETECTED AN ODOR IN THE COCKPIT. CONTINUED THE CLIMB, LEVELING AT 16000 FT WHERE THE ODOR WAS THE STRONGEST. NO SMOKE WAS VISIBLE BUT SMELLED LIKE WIRE INSULATION BURNING. ISOLATING THE PNEUMATICS DID NOT REDUCE THE ODOR. REMOVED AND REPLACED THE AHRS UNIT. PERFORMED A SATISFACTORY OPS CHECK OF THE AHRS SYS. WORK PERFORMED IAW AMM 34-22-00 WITH NO FURTHER DEFECTS NOTED AT THIS TIME.