ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Engine Will Not Crank or Cranks Slowly (Air Starter)

Symptom Tree  t077

This is symptom tree t077
Cause Correction

Air pressure is low in the air tanks

Increase air pressure with an external air source. Refer to the OEM service manual.


Electronic fault codes active or high counts of inactive fault codes

Read the fault codes with an electronic service tool. Refer to Section TF in Troubleshooting and Repair Manual, ISB, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL and QSL9 Engines, CM850 Electronic Control System, Bulletin 4021416 or Troubleshooting and Repair Manual, Electronic Control System, ISC, QSC8.3 and ISL Engines, Bulletin 3666271.


OEM starter interlock devices engaged

Check the starter interlock devices. Refer to the OEM service manual.


Lubricating oil pressure switch, gauge, or sensor is malfunctioning or is not in the correct location

Check the oil pressure switch, gauge, or sensor for correct operation and location. Refer to the OEM service manual.


Engine-driven units are engaged

Disengage engine-driven units.


Starting motor is malfunctioning or starting motor is not correct

Check the starting motor operation. Compare the starting motor with the engine and vehicle specifications. Refer to the OEM service manual.


Starting motor pinion or ring gear is damaged

Remove the starting motor, and inspect the gear. Refer to Procedure 013-020.


Lubricating oil level is above specification

Check the oil level. Verify the dipstick calibration and oil pan capacity. Fill the system to the specified level. Refer to Procedures 007-009 and 007-037.


Lubricating oil does not meet specifications for operating conditions

Change the oil and filters. Refer to Cummins Engine Oil Recommendations and Specifications, Bulletin 3810340.


Crankshaft rotation is impaired

Check the crankshaft for ease of rotation. Refer to Procedure 001-016.


Hydraulic lock in a cylinder

Remove the injectors and rotate the crankshaft. Look for the source of fluid in the cylinder. Refer to Procedure 006-026.


Internal engine damage

Analyze the oil and inspect the filters to locate an area of probable damage. Refer to Procedure 007-083.

Last Modified:  29-Jul-2005