Cummins fault code 3845
Cruise Control Disable Command: condition exists
What it means
Cummins' description: Cruise Control Disable Command - Condition Exists.
SPN 5603 is Cruise Control Disable Command. FMI 31 means the ECM has confirmed the condition described in the code is happening.
The accelerator pedal has position sensors and an idle validation switch so the ECM knows exactly what the driver is asking for. Cruise control, brake and clutch switches, PTO and vehicle speed inputs are also monitored.
What the lamp means
This code normally doesn't turn on a dash lamp. It's logged in the ECM for a technician to see, and often explains another active code.
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.
Keep an eye on it
A pedal or switch code that set once and cleared, and the pedal works normally.
Schedule a repair
Cruise doesn't work, the pedal feels dead in spots, or the code keeps returning. Have the pedal or switch checked.
Stop and get help
Engine stuck at idle or the pedal not responding, especially with a red lamp. Don't drive it in traffic. You won't have reliable throttle.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Pedal sensors disagreeing with each other
- Switch inputs that don't make sense together, like brake and throttle at once
What you can check before calling
- Check whether the engine stays at idle no matter what you do with the pedal
- Look at the pedal connector under the dash
- Check whether cruise control works
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
Engines and sources
Listed by Cummins for: QSB 6.7, QSL 9, QSF 3.8. 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: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.
Same SPN, other failure types
Related Accelerator pedal and driver controls codes
- 3844 SPN 5605 FMI 31
Cruise Control Pause Command: condition exists - 3842 SPN 596 FMI 13
Cruise Control Enable Switch: out of calibration - 3841 SPN 596 FMI 2
Cruise Control Enable Switch: erratic or intermittent signal - 3839 SPN 596 FMI 7
Cruise Control Enable Switch: not responding / out of adjustment - 3735 SPN 2884 FMI 9
Engine Auxiliary Governor Switch: abnormal update rate - 3641 SPN 748 FMI 9
Transmission Output Retarder: abnormal update rate
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 3845 mean?
Cummins fault code 3845 is J1939 SPN 5603 FMI 31: Cruise Control Disable Command - Condition Exists. In plain terms: cruise control disable command: condition exists.
Can I keep driving with Cummins code 3845?
Usually, yes. This code doesn't normally turn on a lamp by itself, but check for other active codes that might be more serious. Look at the green, yellow and red examples on this page to judge your situation.
What is the SPN and FMI for Cummins code 3845?
SPN 5603 identifies the part or system (Cruise Control Disable Command). FMI 31 describes the type of failure: condition exists.
What usually causes Cummins code 3845?
The most common causes are: pedal sensors disagreeing with each other; switch inputs that don't make sense together, like brake and throttle at once.
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.