What was found
AIRCRAFT WAS GROUNDED: #1 ENG MODE FAULT CAME ON IN CLIMB AROUND 23000. WE DID ECAM PROCEDURE CONTINUED CLIMB AT LEVEL OFF 330. WE COULD NOT MAINTAIN SPEED. WE TOLD ATC FOR LOWER ALTITUDE AND RETURNED TO DFW. POWER WAS BACK DESCEND THRU MID 20S. THROTTLE SPLIT WAS 3/4 WITH NO HELP. LEVERS WERE UP TO CUB STOP. AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO DFW WHERE IT LANDED SAFELY WITHOUT FURTHER INCIDENT. REPLACED ENGINE ELECTRONIC CONTROL AND IGNITION SUPPLY HARNESS (AALA202103099025) AND PT2 / T2 CABLE ASSEMBLY (AALA202103129012). A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.