Case IH CH – Transmission Controller (TCU) and Electronic Instrument Cluster (EIC): Oil Temperature Above 105 Degrees Centigrade

An informational/calibration code that appears on the digital display during the Semi-Powershift transmission calibration procedure, alerting that the transmission/hydraulic oil temperature is currently exceeding 105°C (221°F).

• MXM
• MXM 120
• MXM 130
• MXM 135
• MXM 140
• MXM 150
• MXM 155
• MXM 165
• MXM 175
• MXM 190

1. 1

   Verify operating conditions: Determine if the code is appearing during a routine transmission calibration (normal prompt) or during field operation.

2. 2

   Check fluid and coolers (if genuinely overheating): Check the transmission/hydraulic oil level and inspect the hydraulic oil cooler for blockages like dirt, chaff, or debris that would restrict airflow.

3. 3

   Test the sensor resistance (if erroneous reading is suspected): Disconnect the transmission oil temperature sensor harness and use a multimeter to measure resistance across the sensor pins to chassis ground. Resistance should scale inversely with temperature.

4. 4

   Inspect the wiring harness: Check the wiring from the temperature sensor to the instrument controller for a short to ground or an open circuit, which can cause a default maximum temperature reading.

1. 1

   Acknowledge calibration prompt

   If the code appears during calibration (Normal Operation), acknowledge the prompt by pressing the 'Upshift' button on the transmission controller to proceed with the calibration.

2. 2

   Cool down tractor

   Alternatively, allow the tractor to idle and cool down until the oil temperature drops into the optimal calibration range (Code 'CL' - between 10°C and 60°C).

3. 3

   Prepare tractor for sensor replacement

   If diagnostic tests prove the sensor has failed internally and needs replacement, park the tractor on a level surface, engage the parking brake, and turn off the engine.

4. 4

   Locate sensor

   Locate the transmission oil temperature sensor on the transmission housing/gearbox case.

5. 5

   Disconnect harness

   Disconnect the electrical harness connector from the sensor.

6. 6

   Place drain pan

   Place a clean drain pan underneath the sensor port to catch any hydraulic/transmission fluid that escapes.

7. 7

   Remove faulty sensor

   Unscrew the faulty sensor from the transmission case.

8. 8

   Install new sensor

   Thread the new OEM sensor into the port. Ensure thread sealant is applied if it is not pre-applied to the new part (many use a 3/8"-18 NPT thread).

9. 9

   Reconnect harness

   Reconnect the electrical harness.

10. 10

    Check fluid level

    Check the transmission fluid level and top off any oil lost during the swap.

11. 11

    Verify repair

    Start the tractor and verify that the temperature gauge reads correctly on the instrument cluster without throwing an error code.