Engine Coolant Temperature High Shutdown Fault
The CAT-TH-110-0 (CAT C3.4 / C7.1) diesel fault code means: Engine Coolant Temperature High Shutdown Fault. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- moderate
- Estimated cost
- DIY cleaning and fluid top-off $20-$80 in materials. Thermostat replacement $150-$300 parts and labor at a CAT dealer. Water pump replacement $400-$900. Head gasket repair $2,500-$5,000 or more depending on engine model and labor rate.
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Common Symptoms
- Instrument cluster LCD displays SPN 110 FMI 0 and machine shuts down without warning
- Engine stops abruptly at high load or during extended duty cycles in hot weather
- Red warning lamp illuminates on the cab cluster immediately before or during shutdown
- Coolant temperature gauge climbs into the red zone before shutdown occurs
- Machine will not restart until coolant temperature drops and fault is cleared
- Visible steam or coolant smell from engine compartment after shutdown
- CAT ET software shows active DTC for SPN 110 FMI 0 with high-temperature event timestamp
Probable Causes (Ranked by Likelihood)
- Plugged or debris-covered radiator core restricting airflow, especially common on dusty summer job sites Very Likely
- Low coolant level due to slow leak at hose, clamp, water pump, or head gasket Very Likely
- Cooling fan clutch slipping, fan belt broken or loose, reducing airflow through radiator Likely
- Thermostat stuck closed, preventing coolant from circulating through the radiator Likely
- Water pump worn or impeller damaged, reducing coolant flow rate through the system Possible
- Coolant temperature sensor (SPN 110) drifted out of calibration or has a wiring fault causing false shutdown Possible
- Internal engine issue such as head gasket failure causing combustion gases to enter coolant circuit Less Likely
Step-by-Step Diagnostic Procedure
Before touching anything, let the engine cool completely. Do not open the coolant cap while the system is hot. Check the coolant overflow tank and radiator fill neck for fluid level. Coolant should be at or near the FULL mark cold.
Walk around to the front of the machine and inspect the radiator core face for packed debris. On telehandlers working in grain, hay, or demolition environments, the core can seal over completely within a shift. Use low-pressure compressed air blown from the clean side outward to clear debris. Do not use a pressure washer directly on the core fins.
With the engine cold, start the machine and watch the temperature gauge during warmup. If the gauge climbs immediately and rapidly before the engine reaches normal operating temperature, suspect a stuck-closed thermostat or a blocked coolant passage.
Check the fan belt condition and tension. A loose or glazed belt will slip under load, especially when the A/C compressor engages. Inspect the fan clutch by trying to spin the fan by hand with the engine off and cold. A fully engaged fan should resist rotation. If it spins freely and easily, the clutch is likely failed.
Inspect all coolant hoses for soft spots, cracks, or collapsed sections, especially the lower radiator hose which can collapse under suction if the internal spring wire is corroded. Check hose clamps for tightness.
Connect CAT ET software via the J1939 service port and pull the active and logged DTC history. Review the coolant temperature parameter data log to see how quickly the temperature rose and whether the sensor reading matches expected warmup curves. A sensor reading over 230 degrees F at idle shortly after a cold start points to a sensor or wiring fault rather than an actual overheating condition.
If coolant level is repeatedly low with no visible external leak, pressure-test the cooling system to 13 PSI and watch for drops. Also check the engine oil dipstick for a milky or frothy appearance, which indicates coolant mixing with oil through a failed head gasket. This step requires professional repair.
After clearing the fault with CAT ET or by key-cycle after cooldown, monitor the machine through a full work cycle. If SPN 110 FMI 0 returns within one shift after cleaning the radiator and confirming coolant level, proceed to thermostat and water pump inspection. Those components require disassembly and are advanced-level repairs.
Frequently Asked Questions
What does CAT telehandler code 110-0 mean?
It means the ECM detected that engine coolant temperature exceeded the shutdown threshold, which is typically around 221 to 230 degrees F depending on the engine model. The ECM shuts the engine down automatically to prevent internal damage. SPN 110 is the J1939 identifier for coolant temperature, and FMI 0 means the value was above the normal operating range.
Can I keep operating the telehandler with this code active?
No. FMI 0 on SPN 110 is a hard shutdown fault. The engine will not run while the fault is active and coolant temperature remains elevated. Do not attempt to bypass the shutdown. Running an overheated diesel engine even briefly can warp the cylinder head or seize the engine.
How much does it cost to fix a 110-0 overheating shutdown?
It depends entirely on the root cause. Cleaning a plugged radiator and topping off coolant might cost $20 to $80 in materials if you do it yourself. A thermostat is $150 to $300 at a CAT dealer. A water pump runs $400 to $900. If the head gasket has failed from repeated overheating events, you are looking at $2,500 to $5,000 or more. Start with the free checks first.
Why does this code keep coming back on my telehandler during summer jobs?
Summer construction sites combine high ambient temperatures with airflow-killing debris like cut grass, dirt dust, and concrete powder. The radiator and oil cooler cores on the TH3510D and TH514D are stacked close together and clog quickly. Make radiator core cleaning part of your daily walkaround during hot weather. A clean core and correct coolant level will prevent most repeat 110-0 faults.