Code Details
| Display code | SPN 110 FMI 0 |
|---|---|
| SPN | 110 |
| FMI | 0 |
| OEM code | None listed |
| Manufacturer | PACCAR |
| System | Engine �?cooling system |
| Component | Engine coolant temperature sensor / cooling system |
| Source address | Unknown or not applicable |
| Severity | stop safely |
| Review status | source backed |
| Source confidence | medium |
| Last reviewed | 2026-06-11 |
Plain-English Meaning
The MX-13 cooling system must manage significant heat output at full load. When coolant temperature rises above the normal range, the ECU's fan control, coolant flow, and thermal management systems are not keeping up with heat rejection. Identify and resolve the underlying cause before damage occurs. On Kenworth T680, T880, and Peterbilt 579 trucks with the PACCAR MX-13, the cooling system fan clutch is viscous and electronically controlled. DAVIE4 and PACCAR ESA display fan clutch status in real time. A thermostat that opens too late — or not at all — prevents the radiator from receiving hot coolant at the correct threshold, which delays fan activation and allows temperature to rise. A thermostat test under operating conditions is straightforward: monitor coolant temperature in DAVIE4 and confirm the thermostat opens at the expected coolant temperature set point.
SPN 110 FMI 0 is Engine Coolant Temperature above normal. On the PACCAR MX-13, the ECU monitors coolant outlet temperature and manages the viscous fan clutch accordingly. DAVIE provides real-time coolant temperature data and fan engagement confirmation. The fault may accompany SPN 1569 FMI 31 if the engine protection system has activated a derate in response to the high temperature.
Common Symptoms
- High coolant temperature warning lamp
- Possible engine protection derate
- Rapid temperature rise under heavy load conditions
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Low coolant level
- Thermostat stuck closed
- Radiator or CAC airflow blocked
- Viscous fan clutch not responding to control commands
- Water pump failure
- EGR cooler internal leak adding heat load to the system
First Checks
- Check coolant level in the expansion tank
- Inspect radiator and CAC face for debris blockage
- Connect PACCAR DAVIE and monitor coolant temperature and fan engagement status
- Check for external coolant leaks
- Monitor fan clutch activation in DAVIE4 during a warming drive cycle
- Verify thermostat opening temperature by monitoring coolant temperature in DAVIE4
Can I Keep Driving?
Reduce load and stop if temperature continues to climb. Operating above the protection threshold risks permanent engine damage.
Related Codes
Related Lookup Pages
Sources
- PACCAR / Kenworth / Peterbilt Service Support — MX Engine Resources PACCAR Inc. · oem · accessed 2026-06-11 · confidence medium
Source: PACCAR Inc., PACCAR / Kenworth / Peterbilt Service Support — MX Engine Resources. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - PACCAR Engine Technical Services PACCAR Inc. · oem · accessed 2026-06-10 · confidence medium
Source: PACCAR Inc., PACCAR Engine Technical Services. 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 the cooling system on the PACCAR MX-13 different between Kenworth T680 and Peterbilt 579 installations?
The MX-13 engine cooling hardware is the same across Kenworth and Peterbilt applications. Differences exist in the truck's hood and airflow management packaging, which can affect how efficiently air is directed through the radiator and CAC. Both use the same DAVIE diagnostics and engine ECU cooling controls.
Can a clogged charge air cooler cause high coolant temperature on the PACCAR MX-13?
A clogged charge air cooler (CAC) does not directly heat the coolant, but reduced charge air cooling increases intake air temperature, which raises combustion temperatures and ultimately adds more heat to the coolant circuit. A severely clogged CAC can therefore contribute to coolant temperature rise in addition to causing intake air temperature faults.
How does PACCAR DAVIE help diagnose SPN 110 FMI 0 on the MX-13?
DAVIE displays coolant temperature, fan clutch engagement duty cycle, thermostat inlet temperature (if equipped), and coolant flow parameters simultaneously. This allows the technician to see whether the fan is engaging correctly when the temperature rises, whether the thermostat is opening at the right temperature, and whether the coolant temperature spike is sudden or gradual �?each pattern suggesting a different fault.