Cummins fault code 598
Electrical Charging System Voltage Low: reading below normal (most severe)
What it means
Cummins' description: Electrical Charging System Voltage Low - Critical Level.
SPN 167 is Electrical Charging System Voltage Low. FMI 1 means the sensor is working, but the value it reports is far below where it should be. This is the most severe 'low' level.
The ECM needs clean, steady battery voltage, and it supplies regulated 5-volt power to many sensors. Voltage problems can cause strange codes across many systems at once.
What the lamp means
A red stop lamp means Cummins treats this as serious. Stop the engine as soon as you can do it safely and get it checked before running it again.
Green, yellow, red: three ways this can look
The same code can be a quick fix or a reason to shut down. Match your situation to the closest example. Cummins rates this a red stop lamp code, so if the red lamp is on, go by the red example.
Keep an eye on it
A low-voltage code after a hard winter start or after the truck sat a while, then clears.
Schedule a repair
Codes return, the truck is slow to crank, or voltage reads low while driving. Test the charging system soon.
Stop and get help
Engine dies, several systems drop out at once, or the ECM loses power. Don't run it until the power supply is fixed. It can leave you stranded.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Weak batteries
- Failing alternator
- Parasitic drain
What you can check before calling
- Check battery terminals and ground straps for corrosion or looseness
- Have the batteries and alternator tested
- Note if several unrelated codes appeared at the same time
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers. For the bigger picture, read our guide: Bad alternator or bad battery? How to tell.
Engines and sources
Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Diagnostic Fault Codes for Cummins Engines. Always confirm with Cummins service information (QuickServe) for your engine serial number.
Same SPN, other failure types
Related Battery, power supply and sensor supply codes
- 585 SPN 677 FMI 4
Starter Relay Driver Circuit: circuit voltage low / shorted low - 584 SPN 677 FMI 3
Starter Relay Driver Circuit: circuit voltage high / shorted high - 621 SPN 1137 FMI 18
Low #1 LB Cylinder Power: reading below normal (moderately severe) - 622 SPN 1138 FMI 18
Low #2 LB Cylinder Power: reading below normal (moderately severe) - 623 SPN 1139 FMI 18
Low #3 LB Cylinder Power: reading below normal (moderately severe) - 624 SPN 1140 FMI 18
Low #4 LB Cylinder Power: reading below normal (moderately severe)
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does Cummins fault code 598 mean?
Cummins fault code 598 is J1939 SPN 167 FMI 1: Electrical Charging System Voltage Low - Critical Level. In plain terms: electrical charging system voltage low: reading below normal (most severe).
Can I keep driving with Cummins code 598?
No. Cummins assigns this code a red stop lamp. Stop the engine as soon as it's safe and have it checked before running it again. Look at the green, yellow and red examples on this page to judge your situation.
What is the SPN and FMI for Cummins code 598?
SPN 167 identifies the part or system (Electrical Charging System Voltage Low). FMI 1 describes the type of failure: reading below normal (most severe).
What usually causes Cummins code 598?
The most common causes are: weak batteries; failing alternator; parasitic drain.
Diesel down in the Midlands?
We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.