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N14 Base Engine Troubleshooting and Repair Manual – Step Timing Control (STC) Valve is Not Shifting Correctly

Symptom Tree  t120

This is symptom tree t120
Cause Correction

STC system malfunction

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

Lubricating oil pressure is below specification

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

STC system malfunction

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

Rail pressure sensing line is restricted

Check the rail pressure sensing line for restriction.
 
Last Modified:  20-Jan-2004
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