John Deere Engines SPN2630FMI15 Fault Code: Charge Air Cooler Outlet Temperature Signal Slightly High
Also called Engine Shutdown Commanded by Application
Charge Air Cooler Outlet Temperature Signal Slightly High · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 2630 FMI 15 means the John Deere ECU sees the charge air cooler outlet temperature signal running slightly higher than expected while the engine has been running for at least 3 minutes. On OEM engines the ECU references a value of 88° C (190° F). This sets as a Warning, not a shutdown, and the ECU tries to keep normal operating parameters while running.
Medium severity. This is logged as a Warning-level alarm, not an immediate shutdown. The ECU keeps controlling the engine within normal parameters, but ignoring it can lead to reduced cooling efficiency, turbo or EGR related wear, or eventually a more serious high-temperature fault. Diagnose it within the same shift rather than parking the machine immediately.
What does John Deere Engines error code SPN2630FMI15 mean?
.Charge air cooler outlet temperature is the temperature of the compressed intake air after it passes through the charge air cooler (intercooler) and just before it enters the engine. Keeping this air cool improves combustion efficiency and controls engine temperatures under load.
SPN 2630 FMI 15 specifically means the outlet temperature signal read by the ECU is slightly higher than expected for the operating conditions present when the code set, not that the sensor circuit failed electrically. The ECU has been running the engine for at least 3 minutes when it evaluates this condition.
Because this sets as a Warning, the ECU does not shut the engine down. It continues trying to hold normal operating conditions. This gives you a window to investigate airflow, cooling, and sensor issues before the problem escalates to a more severe temperature-related fault.
What triggers a John Deere Engines SPN2630FMI15 code?
The DTC becomes active only after the engine has been running for a minimum of 3 minutes and the charge air cooler outlet temperature signal reads slightly higher than expected for the current operating conditions. On OEM engines, the ECU references a charge air cooler outlet temperature of 88° C (190° F) as part of this evaluation.
Common causes of SPN2630FMI15
- Plugged or dirty air filter restricting intake airflow
- Charge air cooler with external or internal airflow obstructions, or general blockage on or near the radiator
- Loose fan belt or damaged fan shroud, or a malfunctioning cooling fan
- Major exhaust leak, boost leak, or restricted exhaust system
- High intake restriction or air throttle restriction
- EGR flow sensor venturi bracket loose, plugged EGR circuit, or EGR system leak
- Radiator hoses leaking or cracked, bad radiator cap, or improper coolant level
- Excessively high ambient air temperature
- Bad terminals or connector at the charge air cooler outlet temperature sensor, or an open or short in the harness including pinched or melted wires
- Bad charge air cooler outlet temperature sensor itself, or defective engine housing, sensor housing, or O-ring
- Bad turbocharger, VGT vanes sticking, or VGT vane position sensor inaccurate/incorrect
- Bad or outdated ECU software, bad ECU, or bad ECU connector connection
How to troubleshoot John Deere Engines SPN2630FMI15: first checks
- Inspect the air filter and intake system for plugging or restriction, and check for obvious boost or exhaust leaks along the charge air piping
- Visually check the charge air cooler and radiator for external blockage, debris, or damage, and confirm the fan shroud is intact and the fan belt is tight
- Check coolant level, radiator cap condition, and radiator hoses for leaks or cracks, and confirm the cooling fan is operating correctly
- Inspect the charge air cooler outlet temperature sensor connector and terminals for corrosion or looseness, and check the wiring harness for pinched, melted, or shorted wires
- Look at the EGR system for a loose venturi bracket, plugged circuit, or leak, and inspect the turbocharger and VGT vane operation if the above checks are clean
- Confirm ECU software is current and check for a solid ECU connector connection before considering ECU replacement
How the code clears
No separate clearing step is listed for this code. Once the actual cause (airflow restriction, cooling issue, wiring fault, or sensor problem) is corrected and the charge air cooler outlet temperature reads normally after the engine has run past the 3 minute mark, the code should stop being active. Always run the engine and confirm the warning does not return before returning the machine to service.
Frequently asked questions
What does SPN 2630 FMI 15 mean on a John Deere engine?
It means the ECU's charge air cooler outlet temperature signal is reading slightly higher than expected for the current operating conditions. On OEM engines this is referenced against 88° C (190° F), and the code can only become active after the engine has run for at least 3 minutes.
Is SPN 2630 FMI 15 a serious fault?
It is logged as a Warning, not a shutdown code. The ECU keeps the engine running under normal control while trying to maintain proper operating conditions. That said, it points to a real cooling or airflow issue that should be checked out within the same shift.
Will the engine shut down or derate because of this code?
No. For FMI 15 the alarm level is Warning and the ECU continues normal engine control. Derate behavior is associated with a different, more severe related condition, not this specific FMI 15 code.
What are the most common causes of this code?
The most frequently cited causes are a dirty or restricted air filter, a blocked or restricted charge air cooler or radiator area, a loose fan belt or bad cooling fan, low coolant or a leaking radiator hose, and a faulty charge air cooler outlet temperature sensor or its wiring.
How long does the engine need to run before this code can set?
The engine must be running for a minimum of 3 minutes before the ECU will evaluate and potentially set this DTC.
Can I keep operating the machine with this warning active?
The ECU will continue to control the engine within normal parameters, but it is best to diagnose the cooling and airflow system as soon as practical rather than running it indefinitely, since the underlying restriction or cooling problem will not fix itself.
Does this code always mean the sensor is bad?
Not necessarily. A bad sensor or its wiring is only one of many possible causes. Airflow restrictions, cooling system problems, exhaust or boost leaks, and EGR or turbocharger issues are all listed as possible causes that should be checked first.