6.7L Cummins Troubleshooting – Engine Will Not Crank – (Electric Starter)

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, CM2150 Electronic Control System, ISB, ISC, ISL, ISLe, ISDe, and QSB3.3
Engines, Bulletin 4021570.

Battery voltage is low

Check the battery connections. Refer to Procedure 013-007 in Section 13.

Broken, loose, or corroded starting circuit connections

Inspect, clean, and tighten both the positive and negative connections between the starting motor
and battery, including the magnetic switch. Refer to Procedure 013-009 in Section 13.

Battery capacity is below specification

Refer to Procedure 013-007 in Section 13. Replace the batteries if necessary.

OEM starter interlock devices engaged

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

Starting circuit component is malfunctioning

Check the starting circuit components. Refer to the OEM service manual.

Starter solenoid does not make an audible sound

Check the magnetic switch and starter solenoid. Refer to Procedures 013-017 and 013-019 in
Section 13.

Battery cables are not the correct gauge or length

Replace the battery cables with larger gauge or shorter length cables. Refer to the OEM service
manual.

Engine-driven units are engaged

Disengage engine-driven units.

Starter motor malfunction

Check the voltage drop at the starting motor. Refer to Procedure 013-020 in Section 13.

Starting motor pinion or ring gear is damaged

Remove the starting motor, and inspect the gear. Refer to Procedure 013-020 in Section 13.

Crankshaft rotation is impaired

Check the crankshaft for ease of rotation. Refer to Procedure 001-016 in Section 1.

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 in Section 6.

Internal engine damage

Analyze the oil and inspect the filters to locate an area of probable damage. Refer to Procedure
007-083 in Section 7.