CM850 Electronic Control System – FAULT CODE 596

Electrical Charging System Voltage High – Data Valid but Above Normal Operational Range – Moderately Severe Level


Overview

CODE REASON EFFECT
Fault Code: 596
PID: P167
SPN: 167
FMI: 0/16
LAMP: Amber
SRT: 

Electrical Charging System Voltage High – Data Valid but Above Normal Operational Range – Moderately Severe 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
SMALL | MEDIUM | LARGE

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

This fault code is part of the Battery Voltage Monitor feature. The ECM can increase idle speed and deactivate idle decrement switch if idle speedup is enabled. View the Battery Voltage Monitor feature settings using the INSITE™ electronic service tool. Disabling the Battery Voltage Monitor 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 of this fault code:

  • Overcharged batteries caused by a faulty alternator or regulator.

Refer to Troubleshooting Fault Code t05-596

Last Modified:  08-Jul-2010