Detroit DD13 EPA07 (2007-09) Fault Code: SPN 3609 FMI 21 (MCM) Diesel Particulate Filter (DPF) Inlet Pressure Sensor Connector Fault

PROBABLE CAUSES:
1. DPF inlet pressure hose leaks.
2. Entire exhaust system, including aftertreatment system.
3. DPF inlet pressure sensor.
4. DPF inlet pressure sensor harness/connector.
5. Check all connections upstream to the MCM (ATD 10-pin connector, vehicle interface module 31-pin connector, MCM 120-pin connector).
6. Stationary regen.