Kubota E:9104 – Engine ECU: Coolant temperature system malfunction

The system has detected an abnormality in the engine coolant temperature readings. This can be triggered by a failed coolant temperature sensor, damaged wiring, or an actual engine overheating condition. When this code is active, the machine will typically enter a protection mode where engine output and acceleration are limited to prevent severe engine damage.

• SVL65-2
• SVL75-2
• SVL90-2
• SVL95-2s
• SVL97-2
• SSV65
• SSV75
• R065
• R430
• R530
• R630

1. 1

   Check coolant levels in both the radiator and the recovery tank (ensure the engine is completely cold first). Low coolant can cause erratic gauge readings.

2. 2

   Inspect the radiator grille and oil cooler for clogging from dust or debris, which is a common cause of overheating.

3. 3

   Visually inspect the wiring harness and connectors leading to the coolant temperature sensor for chafing, loose connections, or rodent damage.

4. 4

   Test the coolant temperature sensor resistance using a multimeter set to ohms. Resistance should drop as the engine warms up (e.g., 153.9 ohms at 122°F, 51.9 ohms at 176°F, and 27.4 ohms at 212°F). If it reads an open circuit, short, or does not change, the sensor is faulty.

1. 1

   Prepare the Machine

   Park the loader on a firm, level surface. Lower the lift arms to the ground, set the parking brake, and turn off the engine. Wait until the engine is completely cool to avoid severe burns from pressurized hot coolant.

2. 2

   Disconnect Power

   Unhook the negative terminal on the battery to prevent electrical shorts.

3. 3

   Drain Coolant (Partial)

   Remove the radiator cap and open the drain plug to drain enough coolant into a suitable container so that the fluid level drops below the sensor port on the engine block. This prevents coolant from spilling everywhere when the sensor is removed.

4. 4

   Remove the Old Sensor

   Locate the coolant temperature sensor on the engine block (often located near the thermostat housing or at the top/rear of the cylinder head, depending on the engine model). Depress the latch on the wiring harness connector and unplug it. Use a deep socket or wrench to carefully unscrew the sensor.

5. 5

   Install the New Sensor

   Thread the new sensor into the block by hand to prevent cross-threading. Tighten it with a wrench, being careful not to overtighten and damage the engine block threads. Reconnect the electrical harness.

6. 6

   Refill and Test

   Close the radiator drain plug. Refill the radiator with a 50/50 mix of fresh water and Kubota-approved antifreeze. Reconnect the battery, start the engine, and check for leaks. Monitor the temperature gauge to ensure it rises smoothly to operating temperature and verify that the E:9104 code has cleared.