Case IH 212 – Engine Controller (ENG / ECM): Oil Temperature Sensor Voltage is too high

In electronic control systems, a "voltage too high" condition typically indicates that the sensor circuit has an open circuit or is shorted to a positive voltage source (+V). Because the sensor is a thermistor, an open circuit causes the reference voltage to max out, triggering the code.

• MX Magnum
• STX Steiger
• MX Magnum Series Tractors
• TG Series Tractors
• Puma Series Tractors
• Steiger Series Tractors
• Axial-Flow Combines

1. 1

   Inspect the wiring harness running from the Engine Controller to the Engine Oil Temperature Sensor for chafed wires, broken wires (open circuit), or melted insulation (short to power).

2. 2

   Disconnect the sensor and inspect the connector pins for corrosion, moisture, or bent pins that could cause an open circuit.

3. 3

   With the key ON and the sensor disconnected, check the reference voltage at the connector and check the signal wire for continuity back to the Engine Controller.

4. 4

   Measure the resistance across the sensor's terminals with a multimeter. If the sensor reads as an open circuit (infinite resistance), it has failed internally.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate the Engine Oil Temperature Sensor on the engine block (location varies depending on whether it is a Cummins or FPT engine).

3. 3

   Disconnect

   Unplug the electrical connector from the sensor.

4. 4

   Remove Sensor

   Place a catch pan underneath the sensor area to catch any residual oil. Use a wrench or deep socket to carefully unscrew the faulty sensor from the engine block.

5. 5

   Install New Sensor

   Thread the new Engine Oil Temperature Sensor into the port. Ensure the sealing ring/gasket is in place. Tighten to the engine manufacturer's specific torque rating.

6. 6

   Reconnect

   Plug the electrical connector back into the new sensor, ensuring it clicks and locks securely.

7. 7

   Clear Codes

   Reconnect the battery. Turn the ignition ON and use a diagnostic service tool (like the CNH Electronic Service Tool) to clear the inactive ENG 212 fault code.

8. 8

   Test

   Start the engine, verify that the check engine light remains off, and inspect the sensor area for any oil leaks.