Case IH 3985 – Engine ECU: ISM-IDI Engine ECU Temperature Too High

Indicates a critical condition (triggering a Red warning light) where the internal temperature of the Engine Control Unit (ECU) has exceeded its maximum safe operating threshold.

• skid steer
• SR130
• SR160
• SR175
• SV185
• SR210
• TR270
• L213
• L216
• L218
• L220

1. 1

   Verify if the error exists only temporarily; if intermittent, it may be ignored, but a persistent Red warning requires immediate action.

2. 2

   Perform a visual and environmental inspection to ensure there are no external heat sources abnormally heating the ECU, engine bay ventilation is not obstructed, and the machine's cooling system is functioning properly.

3. 3

   Check for any short circuits in the wiring harness (such as relay output power shorts) that could be causing the ECU to overheat internally.

1. 1

   Replace the Module

   If the fault persists, replace the Engine Controller as a persistent 'Signal Above Range Max' on the ECU temperature indicates hardware failure.

2. 2

   Install the New ECU

   Disconnect the battery, remove the overheated Engine ECU, and install the replacement module.

3. 3

   Software Calibration

   After replacement, connect the CNH Electronic Service Tool (EST).

4. 4

   Restore Parameters

   Follow the prompt in the EST software to execute the 'Appropriate Service Tool Procedure To Restore Self Learning Parameters' so the new ECU can sync with the engine dataset and fuel injection system.