PACCAR PX-8 CM2150 (2007-09) Fault Code: 281 PID: SID 126 SPN: 1347 FMI: 7 Fuel Pump Pressurizing Assembly 1 – Mechanical System Not Responding Properly or Out of Adjustment

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, calibrate the ECM.

Fault Code 281 will most likely come active while operating at a steady state loaded condition. At this condition, commanded fuel pressures are highest and the pump’s pressure balance is affected the most.

If a high pressure seal has failed, pump head drain flow will be excessive. If seal damage has progressed far enough, the engine may not start because of an inability to develop fuel rail pressure.

If the engine will not start, there are two indications that the pump head has malfunctioned:

•The drain flow will be excessive. This can be measured while cranking the engine. Use the following procedure in the ISC and ISL CM2150 Service Manual, Bulletin 4021569. Refer to Procedure 005-227 in Section 5. Use the following procedure in the ISLe CM2150 Service Manual, Bulletin 4021630. Refer to Procedure 005-227 in Section 5.
•The pumping plungers are broken or mechanically stuck. This can be checked by visual inspection. Use the following procedure in the ISC and ISL CM2150 Service Manual, Bulletin 4021569. Refer to Procedure 005-227 in Section 5. Use the following procedure in the ISLe CM2150 Service Manual, Bulletin 4021630. Refer to Procedure 005-227 in Section 5.
If the engine oil level is rising due to the oil and Fault Code 281 is active, the pump head has malfunctioned and must be replaced.

Possible repairs:

1)Replace the fuel gear pump module.
2)Replace the high pressure fuel pump head.
3)If necessary, calibrate the ECM.