Case IH F-1136-20 - ECU – Engine Control Unit (ECU): ECU temperature sensor 2 is too high

The internal temperature sensor inside the Engine Control Unit (ECU) has detected that the module's physical temperature has exceeded its maximum safe operating limit (typically > 109°C to 115°C).

• MAGNUM AFS Connect
• Case IH 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Case IH A8000 / A8800 Sugar Cane Harvesters
• Various Case IH tractors running EEM3/EEM4 engine management systems

1. 1

   Perform a cold start plausibility check using a diagnostic tool to see if the sensor reads impossibly high when the engine is cold.

2. 2

   Inspect the physical mounting location of the ECU for packed chaff, mud, or debris that prevents heat dissipation.

3. 3

   Check for other active fault codes related to engine coolant temperature (e.g., SPN 110) indicating engine overheating.

4. 4

   Inspect the main power and ground harnesses to the ECU for high resistance that could cause excessive current draw and internal heat.

1. 1

   Clear Debris

   If the ECU is covered in debris, thoroughly clean the module's housing and the surrounding engine bay to restore ambient airflow. Clear the error logs and run the machine to see if the code returns.

2. 2

   Address Cooling Issues

   If the engine is running hot, repair the primary cooling system issue (e.g., clean radiators, replace thermostat) before condemning the ECU.

3. 3

   Replace the ECU

   If internal failure is confirmed: Disconnect the negative battery terminal, unplug the main wiring harness connectors, unbolt the ECU from its mounting bracket, and install the replacement ECU. Programming is required using the CNH Electronic Service Tool (EST) or a compatible dealer-level tool to flash the correct engine software/firmware.