Cummins ISM CM870 (2003-06) Fault Code: 596 PID: P167 SPN: 167 FMI: 0/16 Electrical Charging System Voltage – Data Valid But Above Normal Operating Range – Moderately Severe Level. High battery voltage detected by the battery voltage monitor feature.

Description

This fault code is part of the Alternator Failure Warning feature. The ECM can increase idle speed and deactivate idle decrement switch if idle speedup is enabled. Use INSITE? electronic service tool to view the Alternator Failure Warning feature settings. 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)Overcharged batteries caused by a malfunctioning alternator or regulator.

Possible repairs:

1)Charge or replace the battery.
2)Repair or replace the alternator, regulator, and/or OEM wiring to the alternator.