Engine Speed Surges Under Load or in Operating Range

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF for fault code troubleshooting.

Engine speed also surges at idle

Refer to the Engine Speed Surges at Low or High Idle symptom tree.

Moisture in the wiring harness connectors

Dry the connectors with Cummins electronic cleaner, Part Number 3824510.

Accelerator pedal position sensor or circuit is malfunctioning

Check for accelerator pedal or lever restriction. Check the percent throttle reading on an electronic service tool. Check the accelerator pedal position sensor and the circuit. Refer to Procedures 019-085 and 019-086.

Vehicle speed sensor (VSS) or circuit is malfunctioning

Check the vehicle speed sensor and circuit. Refer to Procedures 019-090 and 019-091.

Tailshaft gear is loose

Check for a loose tailshaft gear. Refer to the OEM service manual.

Electronic control module (ECM) calibration is malfunctioning

Verify the ECM calibration is correct. Check the calibration revision history for applicable fixes to the calibration stored in the ECM. Refer to the calibration history spreadsheet Click here to see ecm_calibration_rev_history.xls

on QuickServe® Online or the INCAL™ CD-ROM. Compare the calibration stored in the ECM with the engine rating and the Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, recalibrate the ECM. Refer to the appropriate electronic service tool manual and Procedure 019-032.

Fuel inlet restriction

Check for fuel inlet restriction. Refer to Procedure 006-020 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Fuel pump is malfunctioning

Check the fuel pump output pressure, pulsation damper, and pressure regulator. Replace the fuel pump if necessary. Refer to Procedures 005-011, 005-0016, and 005-031 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Air in the fuel system

Check for air in the fuel system. Refer to Procedure 006-003 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Air intake system restriction is above specification

Check the air intake system for restriction. Clean or replace the air filter and inlet piping as necessary. Refer to Procedure 010-031 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Exhaust system restriction is not within specification

Check the exhaust system for restrictions. Refer to Procedure 011-009 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Engine position sensor (EPS) or circuit is malfunctioning

Check the engine position sensor and circuit. Refer to Procedures 019-038 and 019-039.

Alternator is malfunctioning

Temporarily disconnect the alternator and run the engine. Replace the alternator if necessary. Refer to the OEM service manual.

Vehicle ground circuit has an intermittent open circuit

Check the ground circuit for loose or broken connections. Refer to the OEM service manual.

Electronic control module (ECM) calibration is malfunctioning

Verify the ECM calibration is correct. Check the calibration revision history for applicable fixes to the calibration stored in the ECM. Refer to the calibration history spreadsheet Click here to see ecm_calibration_rev_history.xls

on QuickServe® Online or the INCAL™ CD-ROM. Compare the calibration stored in the ECM with the engine rating and Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, recalibrate the ECM. Refer to the appropriate electronic service tool manual and Procedure 019-032.

Engine brake adjustment is not correct

Adjust the engine brakes. Refer to Procedure 020-001 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.

Camshaft end clearance is excessive

Check the camshaft end clearance. Refer to Procedure 001-008 or 001-065 in the Troubleshooting and Repair Manual N14 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666142, or the Troubleshooting and Repair Manual M11 Series Engines (STC, CELECT™, CELECT™ Plus Models), Bulletin 3666139.