Detroit DD13 EPA07 (2007-09) Fault Code: SPN 3509 FMI 4 (MCM) The 5V Sensor Supply Bank 1 Circuit Failed Low

NOTE: This fault indicates that the Motor Control Module (MCM) detects a short to ground (voltage less than 4.7) on either of the MCM pins, listed in the chart below. Inspect the harness and repair as necessary. Verify repairs.

PROBABLE CAUSES:
1. Disconnect these sensors one at a time. If code goes inactive, replace component: Crank case ventilator speed sensor, intake manifold pressure sensor, fuel rail pressure sensor, water pump speed sensor, hydrocarbon doser pressure in sensor, hydrocarbon doser pressure out sensor, oil pressure sensor, camshaft position sensor, fan speed sensor, EGR delta P sensor, intake throttle valve, LPPO fuel pressure sensor.
2. Engine sensor harness.
3. MCM2.1 (Engine ECM).