Diagnostic Overview
Detroit Flash Code 47 is an older style Detroit/DDEC code that may relate to air-system or turbo-related diagnostics depending on engine generation. Because flash-code meanings vary, it should be mapped to the exact engine model before parts are replaced. In a turbo list, it usually indicates the need to inspect boost, turbo response, or an associated sensor circuit.
Likely Causes
Turbo/boost sensor fault, air-system control issue, harness or connector problem, older DDEC mapped fault, exhaust leak, intake restriction, or calibration-specific condition.
What To Check First
Read the full electronic code list, confirm the flash-code chart for the engine serial number, then inspect boost pressure data, turbo operation, intake piping, and related sensors. Verify final definition in Detroit DiagnosticLink because FMI meaning can vary by engine year, ACM/MCM calibration, and emissions level.