Case IH 697 – Engine Controller: Engine Controller internal temperature too high

The internal temperature sensor located on the circuit board of the Engine Controller has detected temperatures exceeding its maximum safe operating limit. This can be caused by external environmental factors (lack of airflow, external heat sources), high electrical resistance, or an internal hardware failure within the controller itself.

• MX Magnum
• STX Steiger
• Steiger
• Magnum
• Puma
• Maxxum
• Combines & Harvesters
• Self-Propelled Sprayers

1. 1

   Visual Inspection for Debris: Check the physical location of the Engine ECU for accumulations of dirt, mud, or crop debris that could act as an insulator and prevent normal heat dissipation.

2. 2

   External Heat Sources: Inspect the area around the ECU for missing heat shields or exhaust leaks that might be blowing hot exhaust gases directly onto the controller.

3. 3

   Electrical Ground Check: Test the battery voltage and inspect the ECU ground connections. Poor grounds create high electrical resistance, generating excess heat.

4. 4

   Live Data Monitoring: Using a diagnostic tool (like CNH EST or Jaltest), monitor the live internal temperature reading of the ECU. If it reads impossibly high while cold, the internal sensor has failed.

1. 1

   Cool Down

   Safely shut down the machine and allow the engine compartment and ECU to cool completely.

2. 2

   Clean the Housing

   Thoroughly clean the exterior of the Engine ECU and its mounting bracket to ensure proper airflow.

3. 3

   Resolve Heat Sources

   Repair any exhaust leaks or replace missing/damaged heat shields near the ECU.

4. 4

   Service Connections

   Disconnect the ECU harness connectors and inspect the pins for corrosion, melting, or arcing. Clean the contacts with a dedicated electrical contact cleaner.

5. 5

   Clean Grounds

   Remove, wire-brush, and securely retighten the main ECU ground straps to the chassis and engine block.

6. 6

   Test Operation

   Reconnect the harness, clear fault code 697 using your diagnostic tool, and run the machine under a working load.

7. 7

   Replace ECU

   If the physical environment is clean, the grounds are perfect, and the fault code returns (or the machine goes into derate mode to protect the engine), the ECU has suffered an internal hardware failure and must be replaced.