Cummins ISM CM875 (2003-06) Fault Code: 2551 PID: P129 SPN: 1349 FMI: 0/16 Rear Fueling Actuator Pressure High – Warning. Unexpected high fueling detected on the rear bank.

The ECM estimates the amount of fuel injected into the front and rear banks of the engine by analyzing the acceleration of the crankshaft. This fault is set active when the estimate of fueling on the rear bank is higher than expected.

Possible repairs:

1)Replace the rear fueling actuator.
2)Return the front and rear fueling actuators to their original positions.
3)Replace the rear timing actuator.