Battery Voltage Monitor – Very Low Voltage
|Fault Code: 598
Electrical Charging System Voltage Low – critical level. Very low battery voltage detected by the battery voltage monitor feature.
Red lamp illuminated until very low battery voltage condition is corrected. The electronic control module (ECM) can increase idle speed and deactivate idle decrement switch if idle speedup is enabled.
Battery Voltage Monitor Circuit
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.
The ECM is connected to the battery by the OEM 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 manual for the battery location.
Make sure the ECM battery supply (+) is coming directly from the battery and not the starter.
Possible causes of this fault code:
- Undercharged batteries caused by a faulty alternator or regulator.