Cummins fault code14421 · Engine Main Bearing 8 Temperature Deviation Most Severe
Engine Main Bearing 8 Temperature Deviation Most Severe - Special Instructions
14421 Cummins fault code as shown in INSITE / CaltermSPN1164 · Engine Main Bearing 8 TemperatureFMI14 Special instructionsOBD codenone (J1939 only)LampRed STOP lampCummins textEngine Main Bearing 8 Temperature Deviation Most Severe - Special InstructionsFailure modeSpecial InstructionsWhat Cummins code 14421 means
The ECM has logged Engine Main Bearing 8 Temperature Deviation Most Severe with a special instruction. The exact meaning is specific to this fault code in the Cummins troubleshooting manual rather than a generic electrical failure mode.
It turns on the red STOP ENGINE lamp. Cummins classes this as a fault that can damage the engine or aftertreatment if ignored: stop as soon as it is safe to do so. Many calibrations also apply an engine-protection derate while the fault is active.
On a generic J1939 scan tool, or on the dash of a Freightliner, Kenworth, Peterbilt, International or Volvo chassis, the same fault is shown as SPN 1164 FMI 14 rather than as Cummins code 14421. Cummins INSITE and Calterm show the Cummins number, the SPN / FMI pair and the lamp together.
Custom DTC delete, up to 30 codes, $150. Full DPF / EGR / SCR delete with all related codes and derates, $500. Upload your Calterm .xcal, tick the services, pay with PayPal, and the finished file comes back by email and WhatsApp.
Upload your .xcal →Cummins ECFG / E2M definitions for CM550, CM552, CM554, CM570, CM800, CM850, CM870, CM871 and more: the fault table, torque, fuelling, boost, EGR, DPF and SCR maps, ready for Calterm or WinOLS. Instant download.
Find your ECFG →Other Cummins codes on SPN 1164 Engine Main Bearing 8 Temperature
7 other fault codes share this SPN; each one is a different failure mode (FMI) of the same component.
Related Cummins fault codes
J1939 failure mode identifiers (FMI)
FMI 14 is highlighted. The FMI is the second half of every J1939 fault and tells you how the component failed; the SPN tells you which component.
| FMI | Meaning (SAE J1939-73) |
|---|---|
| 0 | Data valid but above normal operational range - most severe level |
| 1 | Data valid but below normal operational range - most severe level |
| 2 | Data erratic, intermittent or incorrect |
| 3 | Voltage above normal, or shorted to high source |
| 4 | Voltage below normal, or shorted to low source |
| 5 | Current below normal or open circuit |
| 6 | Current above normal or grounded circuit |
| 7 | Mechanical system not responding or out of adjustment |
| 8 | Abnormal frequency, pulse width or period |
| 9 | Abnormal update rate |
| 10 | Abnormal rate of change |
| 11 | Root cause not known |
| 12 | Bad intelligent device or component |
| 13 | Out of calibration |
| 14 | Special instructions |
| 15 | Data valid but above normal operating range - least severe level |
| 16 | Data valid but above normal operating range - moderately severe level |
| 17 | Data valid but below normal operating range - least severe level |
| 18 | Data valid but below normal operating range - moderately severe level |
| 19 | Received network data in error |
| 20 | Data drifted high |
| 21 | Data drifted low |
| 22 | Reserved for SAE assignment |
| 23 | Reserved for SAE assignment |
| 24 | Reserved for SAE assignment |
| 25 | Reserved for SAE assignment |
| 26 | Reserved for SAE assignment |
| 27 | Reserved for SAE assignment |
| 28 | Reserved for SAE assignment |
| 29 | Reserved for SAE assignment |
| 30 | Reserved for SAE assignment |
| 31 | Condition exists |
Questions about code 14421
What does Cummins fault code 14421 mean?
Cummins 14421 is "Engine Main Bearing 8 Temperature Deviation Most Severe - Special Instructions". It maps to SPN 1164 FMI 14. The ECM has logged Engine Main Bearing 8 Temperature Deviation Most Severe with a special instruction. The exact meaning is specific to this fault code in the Cummins troubleshooting manual rather than a generic electrical failure mode.
Which lamp does fault code 14421 turn on?
Red STOP lamp: It turns on the red STOP ENGINE lamp. Cummins classes this as a fault that can damage the engine or aftertreatment if ignored: stop as soon as it is safe to do so. Many calibrations also apply an engine-protection derate while the fault is active.
How do I clear or permanently delete Cummins code 14421?
An active code goes inactive on its own once the condition is gone; the inactive record stays in the ECM fault history until it is cleared with Cummins INSITE (or a J1939 tool that supports the DM3 / DM11 clear). If the code keeps coming back because the part is gone, disconnected or not worth repairing, the lasting fix is to disable fault 14421 in the calibration: upload your .xcal to the ECFG Superstore file service, custom DTC delete from $150 (up to 30 codes), full DPF / EGR / SCR delete $500, and flash the returned file with Calterm or INSITE.
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