Code Details
| Display code | SPN 412 FMI 0 |
|---|---|
| SPN | 412 |
| FMI | 0 |
| OEM code | None listed |
| Manufacturer | Cummins |
| System | Engine — EGR system |
| Component | EGR cooler / EGR temperature sensor |
| Source address | Unknown or not applicable |
| Severity | medium |
| Review status | source backed |
| Source confidence | medium |
| Last reviewed | 2026-06-12 |
Plain-English Meaning
The ISB 6.7 EGR cooler uses engine coolant to reduce the temperature of exhaust gases before they re-enter the intake. When the EGR temperature measured after the cooler is too high, the cooler is not doing its job — either because coolant flow is restricted, the cooler has scaled up internally, the bypass valve is stuck open, or the cooler structure is failing. Overheated EGR gas entering the intake reduces charge density and can accelerate intake system wear over time.
SPN 412 is Engine EGR Temperature in J1939. FMI 0 indicates the temperature is above the normal operating range. On Cummins CM2350 ISB 6.7, the EGR temperature sensor is located after the EGR cooler to measure the cooler's output temperature. A high reading indicates the cooler is not achieving adequate heat rejection. INSITE can display EGR inlet and outlet temperatures, EGR cooler bypass valve position, and coolant temperature together to characterize the cooler's thermal performance and identify the failure mode.
Common Symptoms
- Check engine lamp active
- Higher intake temperature readings from hot EGR gas entering the intake
- Possible coolant consumption if the EGR cooler is developing an internal leak
- Potential for elevated coolant temperatures alongside this fault if EGR cooler bypass is contributing
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Restricted coolant flow through the EGR cooler — scaling, blockage, or low coolant level
- EGR cooler bypass valve partially or fully open, routing uncooled exhaust around the cooler
- EGR cooler internal scaling reducing heat transfer efficiency
- EGR cooler tube failure — internal leak or reduced cross-sectional area
- EGR temperature sensor drifting high
First Checks
- Connect Cummins INSITE and monitor EGR temperature before and after the cooler together with coolant temperature
- Check the EGR cooler bypass valve position in INSITE — a stuck-open bypass valve routes hot exhaust directly to the intake without cooling
- Inspect the coolant system for adequate level and flow to the EGR cooler
- Check for any signs of coolant loss in the exhaust or on the engine that would indicate an internal EGR cooler leak
- If bypass valve and coolant flow are normal but outlet temperature remains high, the cooler internal structure may have failed
Can I Keep Driving?
The ISB 6.7 is typically still driveable with SPN 412 FMI 0 active, but high EGR temperatures affect combustion quality over time. If coolant loss is occurring alongside this fault, the repair is more urgent to prevent engine overheating.
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
Is EGR cooler failure common on the Cummins ISB 6.7?
EGR cooler issues — including bypass valve sticking, internal scaling from degraded coolant, and internal tube failures — are documented service items on many modern diesel engines including the ISB 6.7. The rate of occurrence increases with mileage and is influenced by coolant maintenance practices. Maintaining proper SCA (supplemental coolant additive) concentration and replacing coolant at the specified intervals reduces EGR cooler scaling and corrosion.
Can I check EGR cooler performance without removing it from the engine?
INSITE can provide a significant amount of data about EGR cooler performance without disassembly — comparing inlet and outlet temperatures at various EGR flow rates gives a picture of the cooler's thermal efficiency. A cooler with significantly higher outlet temperature than expected for the coolant temperature and flow rate indicates reduced heat rejection. Physical inspection is needed to confirm internal scaling, bypass valve condition, or structural failure.
Does the ISB 6.7 EGR cooler require a coolant flush when replacing it?
Yes. Replacing the EGR cooler on the ISB 6.7 should be accompanied by a thorough coolant system flush to remove any debris, scale, or contaminants that contributed to the cooler failure. Installing a new cooler without flushing the system can lead to repeated failures as scaling material from the old cooler circulates through the new unit. Follow the Cummins coolant system service procedure including SCA concentration verification after the flush.