Cummins ISB CM850 (2003-06) Fault Code: 271 (Auto) PID: SID 126 SPN: 1347 FMI: 4 High Fuel Pressure Solenoid Valve Circuit – Voltage Below Normal or Shorted to Low Source. Electronic fuel control actuator shorted low.

This fault becomes active when the ECM detects a short circuit in the electronic fuel control actuator circuit. Causes for this fault code are short circuit to ground or low resistance (electronic fuel control actuator coil is shorted internally) in the circuit for the electronic fuel control actuator. When excessive current or a short circuit is detected, the ECM driver to the electronic fuel control actuator is turned off to protect the circuit. It is necessary to cycle the keyswitch off and then back on before the ECM will retest for the cause of the fault code. The ECM driver is activated at key-on; and if the cause is no longer present, the fault code will become inactive and can be cleared. If the fault code is intermittent, look for causes of an intermittent short to ground in the wiring harness or connectors.

Possible repairs:

1)Replace the high-pressure fuel pump.
2)Repair the damaged harness, connector, or pins if possible.
3)Repair or replace the engine harness.
4)Replace the ECM.