Cummins fault code 654
High #4 RB Cylinder Exhaust Temperature: fault
What it means
Cummins' description: High #4 RB Cylinder Exhaust Temperature.
SPN 1146 is High #4 RB Cylinder Exhaust Temperature. FMI (30,45) means the ECM detected a fault in this system.
Large Cummins engines can have an exhaust temperature sensor at each cylinder's exhaust port. Comparing them lets the ECM spot a cylinder that is running hot, cold, or not firing.
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 single exhaust temperature sensor code with the engine running smoothly.
Schedule a repair
The code keeps returning or several cylinders show imbalance. Book diagnosis. It can hide a real cylinder problem.
Stop and get help
Exhaust temperature imbalance with rough running, smoke or a stop lamp. Shut it down. A cylinder running very hot can burn a piston or valve.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Real imbalance from a weak injector or misfire in that cylinder
- Exhaust leak at the manifold
- Valve problem in that cylinder
What you can check before calling
- Look for heat-damaged wiring along the exhaust manifold
- Note any rough running or smoke
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
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 Exhaust temperature sensors codes
- 653 SPN 1145 FMI (30,45)
High #3 RB Cylinder Exhaust Temperature: fault - 655 SPN 1147 FMI (30,45)
High #5 RB Cylinder Exhaust Temperature: fault - 652 SPN 1144 FMI (30,45)
High #2 RB Cylinder Exhaust Temperature: fault - 656 SPN 1148 FMI (30,45)
High #6 RB Cylinder Exhaust Temperature: fault - 651 SPN 1143 FMI (30,45)
High #1 RB Cylinder Exhaust Temperature: fault - 657 SPN 1150 FMI 0
High #7 RB Cylinder Exhaust Temperature: reading above normal (most 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 654 mean?
Cummins fault code 654 is J1939 SPN 1146 FMI (30,45): High #4 RB Cylinder Exhaust Temperature. In plain terms: high #4 rb cylinder exhaust temperature: fault.
Can I keep driving with Cummins code 654?
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 654?
SPN 1146 identifies the part or system (High #4 RB Cylinder Exhaust Temperature). FMI (30,45) describes the type of failure: fault.
What usually causes Cummins code 654?
The most common causes are: real imbalance from a weak injector or misfire in that cylinder; exhaust leak at the manifold; valve problem in that cylinder.
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.