New Holland INST 13021 – Instrument Controller (INST): Transmission Oil Temperature sensor voltage is too low (short to ground)

The Transmission Oil Temperature sensor voltage is too low, specifically caused by a short to ground. The sensor's signal has fallen below the acceptable voltage range, meaning the controller cannot accurately read the transmission fluid temperature.

• TG210
• TG230
• TG255
• TG285
• T8030
• T9020
• T9040
• T7550
• T9.645
• T9.700

1. 1

   Test the resistance of the transmission oil temperature sensor using a multimeter to check for internal failure

2. 2

   Inspect the wiring harness running from the instrumentation controller to the transmission oil temperature sensor for a short to ground (e.g., chafed wires touching the chassis)

3. 3

   Verify the function of the instrumentation controller to ensure the module itself hasn't failed

1. 1

   Locate the Sensor

   Find the transmission oil temperature sensor on the transmission housing.

2. 2

   Disconnect and Test

   Unplug the sensor connector. Measure the sensor's resistance. If the resistance is out of specification (indicating an internal short), remove the old sensor and install a replacement.

3. 3

   Harness Continuity Test

   If the sensor tests good, use a multimeter to check the wiring harness between the sensor connector and the Instrument Controller pins. Test for continuity to ground.

4. 4

   Repair Wiring

   If a short to ground is found in the harness, locate the damaged section of the wire (often caused by rubbing or pinched wires) and repair or replace the harness.

5. 5

   Controller Replacement (Rare)

   If both the sensor and the wiring harness are in good working order, the Instrument Controller has likely failed and will need to be replaced or reprogrammed by a dealer.

6. 6

   Clear Codes

   Once the repair is made, clear the INST 13021 code from the system and operate the tractor to ensure the code does not return.