As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAX FLIGHT NR 2304, RETURN TO GATE. POWERPLANT MESSAGE ON FD DISPLAY DURING TAXI. MAINTENANCE REMOVED AND REPLACED NR 1 PEC BLEED VALVE IAW AMM TASKS 75-31-11-000-801 AND 75-31-11-400-801. GROUND RAN. A/C POWERPLANT MESSAGE DID NOT RETURN. CDS FAULT CODES 725A AND 741A DID NOT COME BACK. AIRCRAFT RETURNED TO SERVICE.