As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURING SMELL NOTED ON FLIGHT DECK DURING TAXI. OPERATED BOTH ENGINES BOTH PACKS TO MAX HOT AND MAX COLD WITH NO DISCREPANCIES NOTED. RAN PACKS WITH APU BLEED WITH NO DISCREPANCIES NOTED. RAN A/C TO HIGHER POWER OPERATED BOTH PACKS. NO DISCREPANCIES NOTED