Symptom Tree t068
| Cause | Correction |
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Electronic fault codes active or high counts of inactive fault codes |
Refer to Section TF in the Troubleshooting and Repair Manual, CM870 Electronic Control System, Signature™ and ISX Engines, Bulletin |
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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 Procedures |
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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 Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, calibrate the ECM. Refer to Procedure |
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Engine is operating in a unique application with a specific calibration |
Check the Performance Options of the calibration stored in the electronic control module (ECM). Use INSITE™ electronic service tool and INCAL™ Calibration DVD_ROM to check the Performance Options section for the specific calibration under Calibration Selection. If the Performance Option reads “Vacuum Truck”, the condition may be normal. A slight oscillation/surging of the engine speed during unloaded PTO is a normal consequence of these unique calibrations. |
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Engine position sensor (EPS) or circuit is malfunctioning |
Check the engine position sensor and circuit. Refer to Procedure |
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Engine speed surges while in the normal operating range and not in PTO or cruise control |
Refer to the Engine Performance Troubleshooting Tree in Section TT. |
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Moisture in the wiring harness connectors |
Dry the connectors with Cummins® electronic cleaner, Part Number 3824510. |
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Engine speed also surges at idle |
Refer to the Engine Performance Troubleshooting Tree in Section TT. |
