ISBe/ISB Series Engines – Alternator Not Charging or Insufficient Charging

Vehicle gauge is malfunctioning

Check the vehicle gauge. Refer to the OEM service manual.

Alternator belt is loose

Check the alternator belt tension. Adjust as necessary. Refer to Section A.

Alternator pulley is loose on the shaft

Tighten the pulley. Refer to Section A.

Electrical system is “open” (blown fuses, broken wires, or loose connections)

Check the fuses, wires, and connections. Refer to the manufacturer’s wiring diagrams.

Battery cables or connections are loose, broken, or corroded (excessive resistance)

Check the battery cables and connections.

Batteries have malfunctioned

Check the condition of the batteries. Replace the batteries, if necessary. Refer to the OEM service manual.

Battery temperature is above specification

Position the batteries away from heat sources. Refer to the OEM service manual.

Alternator or voltage regulator is malfunctioning

Test the alternator output. Replace the alternator or voltage regulator if necessary. Refer to an Authorized Cummins Repair Facility.

Alternator is overloaded, or alternator capacity is below specification

Install an alternator with a higher capacity. Refer to the manufacturer’s instructions.

Electronic fault codes are active

For instructions on how to read active fault codes, refer to Diagnostic Fault Codes in Section 1
. If fault codes are active, contact a Cummins Authorized Repair Facility.