John Deere Engines SPN2790FMI16 Fault Code: Calculated Compressor Outlet Temperature Moderately High
Also called Calculated VGT Compressor Outlet Temperature Moderately High, Calculated VGT Compressor Outlet Temperature Moderately High, Engine Shutdown Commanded by Application
Calculated Compressor Outlet Temperature Moderately High · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 2790 FMI 16 means the ECU has calculated that the turbo compressor outlet air temperature is running moderately above its programmed limit. There is no physical sensor at this location, the ECU derives the value from compressor inlet temperature, turbo speed, and calculated intake air flow. When the fault sets, the ECU issues a warning and derates maximum engine power by up to 50 percent.
High severity. This is set as a Warning level alarm and the ECU responds by cutting maximum available engine power by up to 50 percent. The engine keeps running, but the loss of power can be dangerous during grades, loaded travel, or PTO work, and continued operation risks turbo, charge air cooler, and engine damage if the underlying airflow or cooling restriction is not corrected.
What does John Deere Engines error code SPN2790FMI16 mean?
SPN 2790 FMI 16 is a calculated value fault, not a direct sensor fault. The engine control unit does not have a physical sensor sitting at the turbo compressor outlet. Instead, it estimates outlet air temperature using the compressor inlet air temperature sensor, turbo speed, and a calculated intake air flow rate that itself is built from readings off several other sensors.
When that calculated outlet temperature climbs past a programmed threshold, the ECU logs this code and treats it as a moderately high temperature condition rather than a critical one. Because the value is calculated rather than measured directly, the fault can be triggered either by a genuine airflow or cooling problem, or by a false reading from one of the upstream sensors feeding the calculation.
The ECU response is to derate the engine, cutting maximum available power by up to 50 percent, as a protective measure until the condition clears or is repaired.
Common causes of SPN2790FMI16
- Restricted or dirty air filter limiting intake airflow
- Restricted, damaged, or externally obstructed charge air cooler (CAC)
- Leaking charge air cooler hoses, clamps, or loose connections
- Bad terminals or connector at the turbo compressor inlet air temperature sensor or charge air cooler outlet temperature sensor
- Bad turbo compressor inlet air temperature sensor, charge air cooler outlet temperature sensor, manifold air temperature sensor, or EGR temperature sensor
- Bad terminals, connector, or wiring problem (open or short) at the ECU or in the harness, including the VGT vane position sensor circuit
- Bad or sticking VGT vane position sensor, or turbo vanes sticking on a variable geometry turbocharger
- Damaged VGT or fixed turbocharger
- Internal charge air cooler plugging
- Plugged or damaged EGR cooler or piping
- Low fan speed, loose fan belt, or damaged fan shroud
- Major exhaust, boost, or EGR system leak; air throttle restriction; exhaust restriction
- Extremely high altitude or extremely high ambient temperature increasing compressor inlet air temperature under high load
- Outdated or bad ECU software, or a bad ECU
How to troubleshoot John Deere Engines SPN2790FMI16: first checks
- Check the air filter for restriction and replace if dirty or plugged
- Inspect the charge air cooler (CAC) for external obstructions, damage, or internal plugging, and check all hoses and clamps for leaks or looseness
- Physically pressure test the boost/charge air system for leaks, since a boost leak must be verified by a pressure test, not assumed
- Check the cooling fan: confirm fan speed is not low, the belt is not loose, and the fan shroud is not damaged
- Inspect wiring and connectors at the turbo compressor inlet air temperature sensor, charge air cooler outlet temperature sensor, manifold air temperature sensor, EGR temperature sensor, VGT vane position sensor, and at the ECU itself for corrosion, damage, or looseness
- Look for exhaust system restriction and check the EGR cooler and piping for plugging
- Check for related active DTCs on SPN 107, SPN 1172, SPN 103, SPN 102, SPN 105, SPN 110, SPN 157, SPN 412, SPN 641, SPN 2630, SPN 2791, and SPN 2795 FMI 7, since these are listed in the troubleshooting sequence ahead of this code and should be resolved first
- Confirm the engine software level is current, since outdated ECU software is a listed possible cause
How the code clears
No separate clearing step is listed beyond correcting the underlying cause. The fault is active while the engine is running and the calculated temperature condition is present, so once the airflow restriction, cooling problem, leak, or sensor/wiring fault is corrected, the condition should stop being detected. If a fault is intermittent or was caused by a temporary condition such as extremely high altitude or ambient temperature, it may not require a repair beyond confirming no physical fault exists.
Frequently asked questions
What does SPN 2790 FMI 16 mean on a John Deere engine?
It means the ECU has calculated that the turbo compressor outlet air temperature is moderately above its programmed limit. There is no physical sensor at that location, the value is calculated from other sensor inputs, and the ECU responds with a warning and an engine power derate of up to 50 percent.
Why is my John Deere engine losing power with this code?
The ECU intentionally derates maximum engine power by up to 50 percent as a protective response when this fault is active. This is not a malfunction of the throttle or fuel system, it is a deliberate power reduction tied to the temperature calculation.
Is this code caused by a bad sensor or an actual overheating problem?
It can be either. Since the compressor outlet temperature is calculated rather than measured, a genuine airflow restriction, boost leak, or turbo problem can trigger it, but so can a false reading from the compressor inlet temperature sensor, turbo speed input, or another sensor used in the calculation.
Can a dirty air filter cause SPN 2790 FMI 16?
Yes, a restricted or dirty air filter is listed as a possible cause because it limits intake airflow, which affects the calculated compressor outlet temperature.
Do I need to pressure test the boost system for this code?
Yes, a boost leak should be confirmed with a physical pressure test rather than assumed, since leaking charge air cooler hoses, clamps, or a damaged charge air cooler are listed among the possible causes.
What other codes should I check before diagnosing SPN 2790 FMI 16?
Check for and resolve any active codes on SPN 107, SPN 1172, SPN 103, SPN 102, SPN 105, SPN 110, SPN 157, SPN 412, SPN 641, SPN 2630, SPN 2791, and SPN 2795 FMI 7 first, since these sit earlier in the listed troubleshooting sequence.
Can high altitude or hot weather trigger this fault on its own?
Yes, extremely high altitude or extremely high ambient temperature combined with high engine loads can raise the compressor inlet air temperature enough to trigger a moderately high calculated compressor outlet temperature, even without a mechanical fault.