Diagnostic Overview
MaxxForce fault code SPN 103 FMI 15 is commonly associated with turbocharger speed being above the expected operating range at a least severe level. The ECM is monitoring turbo speed and may take action to protect the turbocharger if speed approaches limits. This can be caused by boost leaks, exhaust leaks, air restrictions, sensor faults, or turbo control problems. It may also appear with derate or air-management faults.
Likely Causes
Charge-air leak, exhaust leak, sticking turbo control mechanism, faulty turbo speed sensor, intake restriction, failed boost sensor, incorrect VGT control, or engine operating near turbo speed limit.
What To Check First
Inspect charge-air piping and cooler for leaks, check exhaust leaks before the turbo, compare boost and turbo speed data, inspect air filter restriction, and check turbo actuator/control operation.