Cummins ISL CM850 (2003-06) Fault Code: 442 PID: 168 SPN: 168 FMI: 0 Battery 1 Voltage – Data Valid but Above Normal Operational Range – Moderately Severe Level. ECM supply voltage is above the maximum system voltage level.

Cummins ISL CM850 (2003-06) Fault Code: 442 PID: 168 SPN: 168 FMI: 0 Battery 1 Voltage – Data Valid but Above Normal Operational Range – Moderately Severe Level. ECM supply voltage is above the maximum system voltage level.

This fault code is logged when the ECM battery supply voltage exceed 36 volts. C

Possible causes :

1)Faulty alternator or regulator that is overcharging the system
2)Batteries connected in series instead of parallel
3)Incorrect jump-starting procedure.

Possible repairs:

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