Diagnostic Overview
Detroit Flash Code 1115 appears to be a combined or reformatted flash-code entry rather than a standard modern SPN/FMI format. In the turbo category, it should be treated as a turbo/air-system related fault that needs to be mapped to the exact Detroit controller and engine generation. The actual repair depends on the matching SPN/FMI and live data.
Likely Causes
Turbo speed or boost fault, VGT control issue, pressure sensor fault, older DDEC flash-code mapping, wiring problem, or calibration-specific air-management fault.
What To Check First
Confirm the exact code format in DiagnosticLink or DDEC software, identify the matching SPN/FMI, then check boost pressure, turbo speed, actuator response, intake leaks, and exhaust leaks. Verify final definition in Detroit DiagnosticLink because FMI meaning can vary by engine year, ACM/MCM calibration, and emissions level.