Case IH 3844 – ENGINE: Fuel Injector 1 Calibration Error or Intake Temperature Sensor Plausibility Error

Depending on the engine and controller generation, this code indicates either that the energizing time for cylinder 1's fuel injector has exceeded the maximum allowable limit during calibration, or that the temperature sensor upstream of the cylinder inlet has drifted and failed a plausibility check.

• skid steer
• Farmall series (95U, 105U, 115U)
• Maxxum series (100, 110, 115, 120, 125, 130, 140)
• Puma tractors
• MXU tractors
• Steiger tractors
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   If diagnosing the Temperature Sensor: Perform a cold soak test by turning the ignition on with the engine stopped (cold engine) and comparing the intake temperature sensor reading to the engine coolant temperature to check for sensor drift.

2. 2

   If diagnosing the Temperature Sensor: Perform an operational test while the engine is running by monitoring live data to ensure the sensor does not deviate excessively from the boost air temperature.

3. 3

   If diagnosing Fuel Injector 1: Connect the CNH Electronic Service Tool (EST) to verify the energizing time of Injector 1.

4. 4

   If diagnosing Fuel Injector 1: Inspect the wiring harness and connectors leading to Injector 1 for shorts, high resistance, or physical damage that could cause a delayed energizing signal.

1. 1

   Identify the exact fault

   Use a diagnostic tool to read the freeze-frame data and confirm whether the 3844 code is flagging the temperature sensor or the cylinder 1 injector.

2. 2

   Wiring Inspection

   Check the harness for the affected component. Repair any chafed wires or corroded pins.

3. 3

   Sensor Replacement (If applicable)

   If the temperature sensor fails the cold soak plausibility check, remove the old sensor from the intake tract upstream of the cylinder inlet and install a new one.

4. 4

   Injector Replacement (If applicable)

   If the injector energizing time is out of specification and the wiring is intact, replace Fuel Injector 1. Note: Service documentation highly recommends replacing the entire set of fuel injectors rather than just one to ensure optimal engine performance and to avoid differences in fuel atomization concentration between old and new parts.

5. 5

   Clear Codes

   Use a DTC eraser or diagnostic tool to clear the fault codes from the Engine ECU. Run the machine under load to ensure the code does not return.