What was found
L ENGINE BLEED CAUTION ON TAKEOFF ROLL. LOW ENERGY REJECTED TAKE OFF FOB AFTER GATE RETURN 29.9 RAN ENGINES HIGH POWER THERE IS A 20PSI SPLIT BETWEEN LEFT AND RIGHT: LEFT ENGINE BLEED IS LOW REQUIRES HEALTH CHECK IF NEEDED PRSOV P/N 19-3611-9-0004 HPSOV PN 19-3611-9-0003 450 THERMOSTAT P/N IS 19-3611-9-9001 PERFORMED LEFT ENG PNEUMATIC SYSTEM HEALTH CHECK OF HPSOV AND HS PILOT NO FAULT OR LEAKS FOUND, BOTH OPERATE NORMAL REF. AMM TASK 36-00-23-705-151-001. ALSO, PERFORMED LEFT ENGINE FAMV SYSTEM PNEUMATIC HEALTH CHECK REF. AMM TASK 36-00-23-705-153-001, TEST FAILED STEP G.21(A)1B, REQUIRES FAN AIR TEMP SENSOR REPLACEMENT. REMOVED AND REPLACED #1 ENGINE FAN AIR TEMP SENSOR PER AMM 36-11-17 UP TO AND INCLUDING STEP 3.F.(6) OF AMM 36-11-17-404-062-001. NEED TO CONTINUE WITH LEAK CHECK OF SENSE LINE AND PANEL 511KT REQUIRES INSTALLATION. PANEL IS ON TOP OF SENSOR, PNEUMAT OFF 19-3611-9-0008 2858 ON 19-3611-9-0008 2634 SENSOR, PNEUMAT OFF 19-3611-9-0008 2858 ON 0000 WING. PARTS USED: 19-3611-9-0008,QTY :1 ROTABLE PARTS CHANGE WAS INDICATED - TT # 1587522 SN OFF 2858 RAN ENGINES, OPS CHECKS GOOD IAW AMM 36-11-08-404-121-001