PACCAR PX-8 CM2150 (2007-09) Fault Code: 271 PID: SID 126 SPN: 1347 FMI: 4 Fuel Pump Pressurizing Assembly 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the fuel pump actuator circuit.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

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 (fuel control actuator coil is shorted internally) in the circuit for the fuel pump actuator. When excessive current or a short circuit is detected, the ECM driver to the 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 test again for the cause of the fault code. The ECM driver is enabled at key-on; 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.

Fault Code 2311 can have high counts if the fault condition is or was intermittent.

Possible repairs:

1)Replace the fuel pump actuator.
2)Repair or replace the engine harness.
3)Replace the ECM.