Case IH 13012 – INST (Instrumentation Controller / Instrument Cluster): Engine Coolant Temperature sensor voltage is too high (open circuit, short to +V)

This indicates that the voltage signal returning from the engine coolant temperature sensor to the controller is higher than the acceptable range, which is typically caused by a broken wire (open circuit), a wire shorting to a power source, or a completely failed sensor.

• MX Magnum
• STX Steiger
• Case IH MX Magnum Series tractors
• Case IH TG Series tractors
• Case IH Steiger Series tractors
• Case IH Axial-Flow Combines

1. 1

   Test the resistance of the engine coolant temperature sensor using a multimeter to check for an internal open or out-of-spec reading

2. 2

   Inspect the wiring harness between the sensor and the instrumentation controller for severed wires (open circuit) or chafed wires touching a power source (short to +V)

3. 3

   Verify that the instrumentation controller is sending and receiving the correct reference voltages

1. 1

   Locate sensor

   Locate the engine coolant temperature sensor on the engine block/coolant manifold.

2. 2

   Test sensor resistance

   Disconnect the sensor and test its resistance. If the sensor reads as an open circuit or is out of the manufacturer's specified resistance range for the current engine temperature, replace the sensor.

3. 3

   Check wiring harness continuity

   If the sensor tests good, use a multimeter to check the continuity of the wiring harness from the sensor connector back to the INST controller pins.

4. 4

   Check for short to power

   Check the sensor signal wire for voltage with the sensor disconnected to ensure it is not shorted to a 12V or 5V power source in the harness.

5. 5

   Repair wiring harness

   Repair any broken wires or replace the damaged section of the wiring harness.

6. 6

   Repair or replace controller

   If the sensor and the wiring harness both test perfectly fine, the instrumentation controller itself has likely failed and will need to be repaired or replaced.

7. 7

   Verify repair

   Clear the fault codes and run the machine to verify the repair.