Detroit DD15 EPA07 (2007-09) Fault Code: SPN 3597 FMI 4 (MCM) Proportional Valve Bank 1 Circuit Failed Low

PROBABLE CAUSES:

For 2007 EPA Engines:
1. Engine brake solenoid.
2. Short to ground between pin 91 of the ECM 120-pin connector and the valve cover fuel injector harness connector (31-pin connector).
3. Short to ground between pin 22 of the 31-pin connector on the vehicle side of he harness and the fan control solenoid.
4. Short to ground between pin 93 of the ECM 120-pin connector and the air seal pressure regulator valve cover.
5. Failed air seal pressure regulator valve.

For 2010 EPA Engines:
1. Inspect the connectors on: DEF pump, pressure limiting unit, diffuser heater, and DEF injection valve.
2. ACM2 (Aftertreatment Control Module) failure.
3. Short to ground between pins 1, 3, or 5 of the ACM2 and pin 2 of the corresponding components.
4. Reconnect components from line #1 one at a time and clear the code after each connection. When the code goes active, this is your failed part.

For 2014 EPA Engines:
1. Engine Jake brake solenoid failure.
2. Front under valve cover fuel injector harness.
3. Short to ground between pin 91 of the 120-pin ECM connection and the valve cover fuel injector harness connector (31-pin).
4. Short to ground between pin 22 of the 31-pin connector on the vehicle side of the harness and fan control solenoid.
5. Short to ground between pin 93 of the 120-pin ECM connection and the air seal pressure regulator valve connector.
6. Air seal pressure regulator valve.