Symptom Tree t068
| Cause | Correction |
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Electronic fault codes active or high counts of inactive fault codes |
Read the fault codes with an electronic service tool. Refer to Section TF for fault code troubleshooting. |
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Engine speed also surges at idle |
Refer to the Engine Speed Surges at Low or High Idle symptom tree. |
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Cruise control/PTO on/off switch or circuit is malfunctioning |
Check the cruise control/PTO on/off switch and the circuit. Refer to Procedure 019-021 and 019-022. |
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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. |
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Vehicle speed sensor (VSS) or circuit is malfunctioning |
Check the vehicle speed sensor and circuit. Refer to Procedure 019-090 and 019-091. |
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Engine position sensor (EPS) or circuit is malfunctioning |
Check the engine position sensor and circuit. Refer to Procedure 019-038. |
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Fuel pump is malfunctioning |
Check the fuel pump output pressure, pulsation damper, and pressure regulator. Replace the fuel pump if necessary. Refer to Procedure 005-016 and 005-031 in the Troubleshooting and Repair Manual, Signature, ISX and QSX15 Bulletin 3666239. |
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Moisture in the wiring harness connectors |
Dry the connectors with Cummins electronic cleaner, Part Number 3824510. |
