Electronic Control System Signature, ISX and QSX15 Engines – Engine Fan Does Not Operate, Operates Erratically, Or Operates Continuously

Electronic fault codes active or high counts of inactive fault codes

View and troubleshoot the fault codes with INSITE™ electronic service tool. Refer to Section TF for the appropriate fault code troubleshooting steps.

Programmable parameters or selected features are not correct

Check the programmable parameters and the selected features with an electronic service tool. Set the parameters and features again if necessary. Refer to Procedure
019-078 in Section 19.

Manual fan ON/OFF switch and circuit is malfunctioning

Check the manual fan ON/OFF switch and circuit. Refer to Manual Fan ON/OFF Switch, Resistance Check, and Short Circuit to Ground Check in Procedures
019-045,
019-380, and
019-381 in Section 19.

Air conditioner sensor or circuit is malfunctioning

Check the air conditioner sensor and circuit. Refer to Procedures
019-261 and
019-262 in Section 19.

Fan clutch actuator or circuit is malfunctioning

Check the fan clutch actuator circuit. Refer to Procedure
019-045 in Section 19.

Engine electrical ground is malfunctioning

Check engine ground to chassis and chassis ground to battery negative (-) post. Refer to the OEM service manual and Procedure
013-009 in the Signature™, ISX and QSX15 Service Manual, Bulletin 3666239.

Electronic control module (ECM) calibration is malfunctioning

Verify the electronic control module (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 Internet Website or the INCAL™ calibration CD. Compare the calibration stored in the ECM with the engine rating and the Control Parts List (CPL), Bulletin 4021326 or 4021327. If necessary, calibrate the ECM. Refer to Procedure
019-032 in Section 19.

Intake manifold temperature or coolant temperature is above the threshold to activate the cooling fan.

Refer to the Intake Manifold Air Temperature Above Specification and/or Coolant Temperature Above Normal – Gradual Overheat symptom trees in Section TS of the Signature™, ISX, and QSX15 Service Manual, Bulletin
3666239.