New Holland 3033 – ECM: Implausible Oil Temperature Sensor Signal

The Engine Control Module (ECM) has registered an invalid or implausible signal from the engine oil temperature sensor. The ECM determines this by comparing the input from the oil temperature sensor with the input from the engine coolant temperature sensor. If the values from these two sensors are not within a believable range of each other, especially during engine start-up or after a period of operation, the ECM logs this fault. This indicates a potential issue with the oil temperature sensor, the coolant temperature sensor, or their associated wiring circuits.

• T7 Series
• T8 Series
• T9 Series
• TG Series
• New Holland combine and harvester models

1. 1

   Visually inspect the wiring harnesses and connectors for both the engine oil temperature sensor and the coolant temperature sensor for damage, chafing, melting, corrosion, or loose pins

2. 2

   Check engine oil and coolant fluid levels to ensure they are correct, as abnormal levels can affect temperature readings

3. 3

   Perform a plausibility check on a cold start (engine off for several hours) by turning the key to 'ON' without starting the engine; oil and coolant temperatures should be very close to each other and ambient air temperature

4. 4

   Start the engine and monitor temperatures during warm-up; the oil temperature should rise slowly and eventually meet or slightly exceed the coolant temperature. Erratic jumps indicate a sensor or wiring problem

5. 5

   Check for other active or stored fault codes related to the oil or coolant temperature sensors

1. 1

   Isolate the faulty sensor

   Based on the diagnostic checks, determine whether the oil temperature or coolant temperature reading is the one providing the implausible value (e.g., stuck at a very low or high value).

2. 2

   Locate the sensor

   The engine oil temperature sensor (often combined with the oil pressure sensor) is typically located on the engine oil filter housing or the side of the engine block. The coolant temperature sensor is usually found on the engine head near the thermostat housing.

3. 3

   Test sensor and circuit

   Disconnect the sensor's electrical connector and check for expected reference voltage with the key on. Test the sensor's resistance in fluids of known temperatures and compare to service manual specifications. If the sensor tests okay, check the wiring harness for continuity and shorts to ground or power between the sensor and the ECM.

4. 4

   Replace faulty component

   If the sensor is determined to be faulty, replace it. It is recommended to drain some engine oil before removing the oil temperature sensor to prevent spillage.

5. 5

   Clear codes and verify repair

   After replacing the sensor or repairing the wiring, clear all fault codes using a diagnostic tool. Operate the machine and monitor the temperature readings to ensure they are plausible and the fault code does not return.