John Deere Engines SPN2630FMI4 Fault Code: Charge Air Cooler Outlet Temperature Signal Out Of Range Low
Also called Charge Air Cooler Outlet Temperature Signal Out of Range Low, Charge Air Cooler Outlet Temperature Signal Out of Range Low, Engine Shutdown Commanded by Application
Charge Air Cooler Outlet Temperature Signal Out Of Range Low · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 2630 FMI 4 means the ECU sees a charge air cooler outlet temperature signal voltage below the sensor's low voltage specification, a value that corresponds to a temperature higher than physically possible. The ECU sets a Warning alarm, substitutes a default charge air cooler outlet temperature of 50° C (122° F), and keeps trying to manage the engine operating envelope with that default value.
Medium severity. This is logged as a Warning-level alarm, not an immediate shutdown code. The ECU compensates with a default temperature value and keeps the engine running within its operating envelope, but the loss of real charge air data means boost and temperature management is degraded until the sensor circuit is fixed.
What does John Deere Engines error code SPN2630FMI4 mean?
SPN 2630 FMI 4 points to the charge air cooler outlet temperature sensor circuit, the sensor that tells the ECU how hot the compressed air is after it passes through the charge air cooler on its way to the intake. The ECU uses this reading to fine-tune fueling, boost, and emissions control based on actual intake air temperature.
With FMI 4, the input voltage from the sensor has dropped below the sensor's specified low voltage range. That low-voltage reading corresponds to a temperature that is not physically possible for air coming out of a charge air cooler, so the ECU flags it as an out-of-range-low fault rather than trusting the number.
When this happens, the ECU throws a Warning alarm and falls back to a default charge air cooler outlet temperature of 50° C (122° F). It uses that default to keep trying to maintain a normal operating envelope, but it is running blind on actual charge air temperature until the real signal is restored.
What triggers a John Deere Engines SPN2630FMI4 code?
The code sets whenever the ignition is on and the charge air cooler outlet temperature signal voltage is below the sensor's low voltage specification, active continuously while that fault condition is present.
Common causes of SPN2630FMI4
- Bad or corroded terminals or connector at the charge air cooler outlet temperature sensor
- Bad charge air cooler outlet temperature sensor itself
- Open or short in the wiring harness between the sensor and the ECU, including melted, pinched, or chafed wiring
- Intermittent short to ground in the sensor circuit
- Bad terminals or connector at the ECU
- Bad ECU
- Bad or outdated ECU software
How to troubleshoot John Deere Engines SPN2630FMI4: first checks
- Inspect the charge air cooler outlet temperature sensor connector for corrosion, moisture, bent pins, or loose terminals before touching anything else
- Trace the wiring harness from the sensor to the ECU looking for melted, pinched, or chafed sections, especially near hot engine surfaces or moving parts
- Check for an open circuit or short (including intermittent shorts to ground) in the harness using a multimeter with the connector disconnected
- Inspect the ECU connector for corroded or loose terminals
- Confirm the ECU software level is current, since outdated software is listed as a possible cause
- If wiring and connectors check out, test or swap the charge air cooler outlet temperature sensor to rule it out before suspecting the ECU itself
How the code clears
No separate clearing step is listed. Once the underlying wiring, connector, sensor, or ECU issue is repaired so the signal voltage returns to a valid range, the fault should stop being active. Because the alarm is active only while the ignition is on and the fault condition is present, verify the repair by cycling the ignition and checking that the code does not reset.
Frequently asked questions
What does SPN 2630 FMI 4 mean on a John Deere engine?
It means the ECU detected a charge air cooler outlet temperature sensor signal voltage below the sensor's low voltage specification, corresponding to a temperature that is not physically possible. It is logged as a Warning.
Will SPN 2630 FMI 4 shut my engine down?
No shutdown is indicated for this specific code. The alarm level is Warning, and the ECU substitutes a default charge air cooler outlet temperature of 50° C (122° F) while trying to maintain normal operation.
Is it safe to keep running the equipment with this code active?
You can typically keep working since it's a Warning-level code, but the ECU is running on a default temperature value instead of real data, so boost and emissions control may not be optimal. Get the sensor circuit diagnosed as soon as practical.
What usually causes this fault?
Most cases trace back to a bad connector or corroded terminals at the sensor or ECU, a bad sensor itself, or wiring problems in the harness such as an open, short, intermittent short to ground, or physical damage like melting or pinching. Outdated ECU software or a bad ECU are less common causes.
How do I fix SPN 2630 FMI 4?
Start by inspecting and cleaning the sensor and ECU connectors, then check the harness for opens, shorts, or damage. If those check out, test or replace the charge air cooler outlet temperature sensor, and confirm ECU software is up to date before considering ECU replacement.
Is there a separate procedure to clear this code once repaired?
No separate clearing step is listed. The fault should stop being active once the signal voltage is restored to a valid range; cycle the ignition and recheck to confirm it does not return.
Does this code affect engine power or performance?
It's not described as a power-limiting or shutdown code by itself, but since the ECU is using a default charge air temperature rather than the real reading, fine control over boost and combustion conditions is reduced until it's fixed.