CM870 and ISX Engines – FAULT CODE 596

Battery Voltage Monitor – High Voltage


Fault Code: 596
PID: P167
SPN: 167
FMI: 0/16
LAMP: Amber

Electrical Charging System Voltage High – warning level. High battery voltage detected by the battery voltage monitor feature.

Amber warning lamp illuminated until high battery voltage condition is corrected.

Battery Voltage Monitor Circuit

Circuit Description

The electronic control module (ECM) receives constant voltage from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. The ECM receives switched battery input through the vehicle keyswitch wire when the vehicle keyswitch is turned on.

Component Location

The ECM is connected to the battery by the ECM power harness. This direct link provides a constant power supply for the ECM. The location of the battery will vary with the OEM. Refer to the OEM troubleshooting and repair manual for the battery location.

Shop Talk

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

Possible causes of this fault code:

  • Overcharged batteries caused by a faulty alternator or regulator.

Refer to Troubleshooting Fault Code t05-596

Last Modified:  01-Sep-2010