As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CHIME ALERTED LEFT ENGINE BLEED TEMP NEARING BLEED TRIP OFF, DURING CRUISE AND DESCENT. THE BLEED REPORT CAPTURED THAT THE PRE-COOLER OUTLET TEMPERATURE REACHED AS HIGH AS 490 °F, RESULTING IN A LOW BLEED DUCT PRESSURE OUTPUT OF 17 PSI. (SYSTEM HAS GONE INTO OVERTEMP PROTECTION MODE) PERFORMED TEST ON LT PRE-COOLER CONTROL VALVE IAW AMM 36-12-00-700-801. CHECK PASSED. REMOVED AND REPLACED 390 SENSOR IAW AMM 36-13-03. LEAK CHECK PASSED.