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Cummins N14 STC, Celect, Celect Plus – Service Manual Step Timing Control (STC) Valve is Not Shifting Correctly

Symptom Tree  t120

This is symptom tree
Cause Correction

STC system malfunction

Check the electrical STC oil control valve and circuit. Refer to Procedure 006-037 in Section 6.
 

Lubricating oil pressure is below specification

Check the oil pressure. Refer to Procedure 007-028 in Section 7. If the pressure is low, refer to the Lubricating Oil Pressure Low troubleshooting symptom tree in Section TS.
 

STC system malfunction

Check the electrical STC oil control valve and circuit. Refer to Procedure 006-037 in Section 6.
 

Rail pressure sensing line is restricted

Check the rail pressure sensing line for restriction.
 
Last Modified:  18-Jan-2012
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