Cummins ISB CM850 (2003-06) Fault Code: 598 PID: 167 SPN: 167 FMI: 11 Electrical Charging System Voltage Low – Data Valid But Below Normal Operating Range – Most Severe Level. Very low battery voltage detected by the battery voltage monitor feature.

Cummins ISB CM850 (2003-06) Fault Code: 598 PID: 167 SPN: 167 FMI: 11 Electrical Charging System Voltage Low – Data Valid But Below Normal Operating Range – Most Severe Level. Very low battery voltage detected by the battery voltage monitor feature.

This fault code is part of the Alternator Failure Warning feature. The ECM can increase idle speed and deactivate idle the decrement switch if Idle Speedup is enabled. View the Alternator Failure Warning feature settings with INSITE? electronic service tool. Disabling the Alternator Failure Warning feature will also disable this fault code.

Make sure the ECM battery supply (+) is coming directly from the battery and not the starter.

Possible causes:

1)Undercharged batteries caused by a malfunctioning alternator or regulator.

Possible repairs:

1)Repair the damaged connections.
2)Tighten the battery connections and clean the battery terminals.
3)Charge or replace the battery.
4)Repair or replace the alternator and/or OEM wiring to the alternator.
5)Repair or replace the battery harness.
6)Repair or replace the OEM power harness.