As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHX - DURING TAXI FROM GATE, CREW NOTED A STRONG BURNING RUBBER ODOR. ACFT RETURNED TO GATE AND MAINTENANCE COMPLIED WITH MEL PROCEDURES FOR 21 01 NR 2 PACK. MX ACTIONS LATER REPLACED THE COMPRESSOR DISCHARGE SENSOR CANNON PLUG. OPS CHECK OK. MEL REMOVED. (Z)