Cummins fault code 234
Engine Crankshaft Speed/Position: reading above normal (most severe)
What it means
Cummins' description: Engine Crankshaft Speed/Position - Data valid but above normal operational range - Most Severe Level.
SPN 190 is Engine Speed. FMI 0 means the sensor is working, but the value it reports is far above where it should be. This is the most severe 'high' level.
The crank and cam position sensors tell the ECM exactly where each piston is so it can time fuel injection. Losing one causes rough running; losing both usually stops the engine.
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
One sensor code that set briefly and cleared, with the engine starting and running normally.
Schedule a repair
Long cranking, occasional stalling, or the code returns. Replace the sensor soon. These usually fail completely without much warning.
Stop and get help
Engine stalls or won't start, or a stop lamp with lost speed signals. Don't plan on driving it until it's fixed.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Real engine overspeed from downhill or a missed shift
- Signal noise from aftermarket electrical add-ons
What you can check before calling
- Note any stalling, hard starting, or rough running
- Look at the sensor connectors for oil or damage
- Think about whether any electrical work was done recently
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, QSX 15, QSB 4.5, QSF 3.8, QSG 12. 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
- 121 SPN 190 FMI 10
Engine Speed/Position Sensor Circuit: abnormal rate of change - 689 SPN 190 FMI 2
Engine Crankshaft Speed/Position: erratic or intermittent signal - 1992 SPN 190 FMI 16
Engine Crankshaft Speed/Position: reading above normal (moderately severe) - 2321 SPN 190 FMI 2
Engine Crankshaft Speed/Position: erratic or intermittent signal - 2468 SPN 190 FMI 16
Engine Crankshaft Speed/Position: reading above normal (moderately severe)
Related Engine speed and position sensors codes
- 283 SPN 1043 FMI 3
Engine Speed/Position Sensor #1 (Crankshaft) Supply Voltage Circuit: circuit voltage high / shorted high - 284 SPN 1043 FMI 4
Engine Speed/Position Sensor #1 (Crankshaft) Supply Voltage Circuit: circuit voltage low / shorted low - 115 SPN 612 FMI 2
Engine Magnetic Speed/Position Lost Both of Two Signals: erratic or intermittent signal - 496 SPN 1043 FMI 11
Engine Speed/Position Sensor #2 (Camshaft) Supply Voltage: root cause not known - 497 SPN 1377 FMI 2
Multiple Unit Synchronization Switch: erratic or intermittent signal - 523 SPN 611 FMI 2
Auxiliary Intermediate (PTO) Speed Switch Validation: erratic or intermittent signal
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 234 mean?
Cummins fault code 234 is J1939 SPN 190 FMI 0: Engine Crankshaft Speed/Position - Data valid but above normal operational range - Most Severe Level. In plain terms: engine crankshaft speed/position: reading above normal (most severe).
Can I keep driving with Cummins code 234?
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 234?
SPN 190 identifies the part or system (Engine Speed). FMI 0 describes the type of failure: reading above normal (most severe).
What usually causes Cummins code 234?
The most common causes are: real engine overspeed from downhill or a missed shift; signal noise from aftermarket electrical add-ons.
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.