Code Details
| Display code | SPN 27 FMI 9 |
|---|---|
| SPN | 27 |
| FMI | 9 |
| OEM code | None listed |
| Manufacturer | Cummins |
| System | Engine �?EGR system |
| Component | EGR valve / position sensor |
| Source address | Unknown or not applicable |
| Severity | medium |
| Review status | source backed |
| Source confidence | medium |
| Last reviewed | 2026-06-11 |
Plain-English Meaning
The ISX15 and X15 use an electronic EGR valve to precisely control exhaust gas recirculation. The ECM monitors the valve position via a sensor and uses that feedback to control EGR flow. When position sensor updates stop arriving on schedule, the ECM cannot verify whether the valve is in the commanded position, which can affect emissions control and engine performance.
SPN 27 is Engine EGR Valve 1 Position in J1939. FMI 9 indicates the data is not being received at the expected update rate �?the message is absent or arriving too slowly. On Cummins CM2350 ISX15/X15 engines, the EGR valve assembly includes an integrated position sensor. When this sensor's signal update rate falls below the expected threshold, the ECM cannot maintain precise EGR control and logs FMI 9. The fault can originate from wiring damage, connector corrosion, sensor failure, or power supply issues to the valve assembly.
Common Symptoms
- Check engine lamp active
- Possible reduction in EGR flow affecting emissions and combustion quality
- Slight increase in exhaust smoke under some load conditions
- EGR-related fault may accompany other aftertreatment codes
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- EGR valve position sensor wiring harness damaged or connector corroded
- EGR valve assembly with integrated sensor failed internally
- Power supply or ground fault at the EGR valve connector
- Internal ECM communication fault in the control architecture
First Checks
- Connect Cummins Insite and check all active and inactive codes �?companion EGR codes can clarify whether the issue is communication, position accuracy, or valve mechanical fault
- Inspect the EGR valve harness connector for corrosion, bent pins, or damaged wiring
- Check the EGR valve power supply and ground circuits at the harness connector
- Use Insite live data to monitor the EGR valve position value �?no update or erratic updates confirm a sensor or wiring issue
- If wiring and power supply are good, the EGR valve assembly with integrated sensor may need replacement
Can I Keep Driving?
With EGR position sensing faulted, the ECM may default to a fixed EGR position or reduce EGR flow. This can affect emissions compliance and may generate additional NOx or DPF loading. The vehicle is typically still driveable, but the fault should be resolved to maintain proper emissions control.
Related Codes
Related Lookup Pages
Sources
- Cummins INSITE Service Tool — Public Reference Documentation Cummins Inc. · oem · accessed 2026-06-11 · confidence medium
Source: Cummins Inc., Cummins INSITE Service Tool — Public Reference Documentation. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - QuickServe Online Cummins Inc. · oem · accessed 2026-05-05 · confidence medium
Source: Cummins Inc., QuickServe Online. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - SAE J1939 Standards Collection SAE International · official · accessed 2026-05-05 · confidence medium
Source: SAE International, SAE J1939 Standards Collection. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
Can the EGR valve be cleaned to fix SPN 27 FMI 9 on the Cummins ISX15?
FMI 9 indicates a communication rate issue, not a mechanical sticking fault (which would typically be FMI 7). Cleaning the valve may not address the communication problem. The diagnosis should focus on the wiring, connector, and power supply at the valve assembly before attempting cleaning or replacement.
Is the EGR valve replaceable on the Cummins ISX15 without removing the engine?
Yes. The EGR valve on the ISX15 and X15 is an externally mounted assembly accessible with the engine in the vehicle. Replacement requires disconnecting the electrical connector and the EGR pipe connections. Cummins Insite may require an EGR system reset and calibration after the valve is replaced.
Will SPN 27 FMI 9 on the ISX15 cause a failed emissions inspection?
An active check engine lamp from this fault would likely cause a visual inspection failure in jurisdictions that check for illuminated MIL lamps. The underlying EGR fault may also affect emissions test measurements, particularly NOx output. Resolve the fault before scheduling an emissions inspection.