John Deere Engines SPN110FMI17 Fault Code: Engine Coolant Temperature Signal Slightly Low
Also called Coolant Temperature Signal Slightly Low
Engine Coolant Temperature Signal Slightly Low · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
SPN 110 FMI 17 means the ECU sees engine coolant temperature reading lower than it should after the engine has been running for 3 minutes. It's a Warning-level code, the ECU keeps operating normally, but running cold for too long can cause other problems like a stuck EGR valve.
Medium severity. This is a Warning-level code and the ECU continues normal operation. It won't stop the machine, but ignoring it can let the EGR valve stick from prolonged cold running, so it should be diagnosed within the shift rather than left indefinitely.
What does John Deere Engines error code SPN110FMI17 mean?
SPN 110 FMI 17 tells you the ECU's coolant temperature sensor signal is coming in lower than the ECU expects for how long the engine has been running. The engine coolant temperature sensor is what tells the ECU when the engine has reached operating temperature, which affects fueling, emissions controls, and cooling fan operation.
This code sets specifically when the engine has been running for 3 minutes and the low-temperature condition is still active. It does not mean the engine is overheating, it means the opposite: the engine isn't warming up like it should, or the sensor is reporting that it isn't.
The ECU logs this as a Warning and keeps running normally, but there's an important side effect. Running an engine at low coolant temperatures for extended periods can eventually cause the EGR valve to stick. Once you've fixed the root cause of this code, you should verify EGR operation using Service ADVISOR and confirm the EGR desired position matches actual position.
What triggers a John Deere Engines SPN110FMI17 code?
The DTC sets when the engine has been running for 3 minutes and the low coolant temperature signal condition is still active.
Common causes of SPN110FMI17
- Bad or stuck-open thermostat that won't let the engine warm up properly
- Bad coolant temperature sensor connector, or corroded/damaged terminals at the sensor
- Bad coolant temperature sensor itself, or a bad engine housing, sensor housing, or O-ring
- Bad terminals or connector at the ECU
- Open or short in the wiring harness, including pinched or melted wires
- High resistance in the harness
- Outdated or bad ECU software
- Bad ECU
- Other active codes that may be tied to the same fault condition
How to troubleshoot John Deere Engines SPN110FMI17: first checks
- Let the engine run to full operating temperature while watching the coolant temperature reading on a diagnostic tool to confirm the low reading is real and not just a display quirk
- Inspect the thermostat for sticking open, since a stuck-open thermostat is one of the most common causes of a signal that never rises to normal temperature
- Check the coolant temperature sensor connector and terminals for corrosion, looseness, or damage, and inspect the sensor housing and O-ring for defects
- Trace the wiring harness between the sensor and the ECU for pinched, melted, open, or shorted wires, and check for high resistance in the harness
- Check the ECU connector for a bad connection, and confirm the ECU software is up to date
- If everything electrical and mechanical checks out, look for other active codes that could be linked to the same symptom
How the code clears
No separate clearing step is listed. Once the root cause is repaired and the coolant temperature signal reads normally through a full warm-up cycle, the code should stop being active. After the repair, run Service ADVISOR and verify the EGR valve's desired position matches its actual position, since prolonged cold running from this fault can cause the EGR valve to stick.
Frequently asked questions
What does SPN 110 FMI 17 mean on a John Deere engine?
It means the ECU's engine coolant temperature signal is reading slightly lower than expected after the engine has been running for 3 minutes. It indicates the engine isn't reaching normal operating temperature, or the sensor signal is reporting that it isn't.
Is SPN 110 FMI 17 a serious problem?
It's logged as a Warning, and the ECU continues to operate normally, so it won't shut the engine down. However, running with low coolant temperature for too long can cause the EGR valve to stick, so it's worth diagnosing promptly rather than ignoring it.
What usually causes this code?
Common causes include a stuck-open thermostat, a bad coolant temperature sensor or its connector, corroded or damaged terminals, an open or shorted harness, high resistance in the wiring, outdated ECU software, or a bad ECU.
Can a bad thermostat cause SPN 110 FMI 17?
Yes. A thermostat that stays open or fails to close properly is one of the listed causes, since it prevents the engine from reaching and holding normal operating temperature.
Do I need to check the EGR valve after fixing this code?
Yes. Running the engine cold for an extended period can cause the EGR valve to stick. After resolving SPN 110 FMI 17, use Service ADVISOR to verify the EGR valve's desired position matches its actual position.
Will this code cause the engine to derate or shut down?
No. For SPN 110 FMI 17, the ECU continues to operate normally. It is only logged as a Warning, unlike some related high-temperature coolant codes that can trigger an engine derate.
How is SPN 110 FMI 17 different from other coolant temperature codes?
FMI 17 specifically indicates a signal that is slightly lower than expected once the engine has been running for 3 minutes. Other FMI codes on the same SPN cover different conditions, such as signals that are much higher than expected, which can trigger a derate instead of just a warning.