Case IH 3750 (DTC EC36) - ECU – Engine Control Unit (ECU): ECU internal failure - Fuel injection energizing time is not plausible.

The Engine Control Unit (ECU) continuously monitors the fuel injector energizing time (the duration the injector is commanded open) for logical plausibility. If the ECU determines that the energizing time value is implausible or illogical for either the pilot, main, or post-injection phases, it logs this internal failure fault.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• 7240
• 8240
• 9240
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 55C
• Farmall 90
• Farmall 100A
• Farmall 115A
• Farmall 120A
• Maxxum
• Puma
• Magnum 250-380
• Steiger 350-620
• Quadtrac
• Patriot 3230
• Patriot 3330
• Patriot 4430
• Titan

1. 1

   Check the battery for sufficient voltage supply. Inspect the main power and ground wiring harnesses leading to the ECU for corrosion, chafing, or loose connections.

2. 2

   Connect the Case IH Electronic Service Tool (EST) or a compatible diagnostic tester. Clear the fault code, start the engine, and perform an overrun test to see if the code returns.

3. 3

   Check if there is a software update or dataset calibration update available for the ECU.

4. 4

   If the wiring is intact, voltage is correct, and the fault code immediately returns after being cleared, condemn the ECU for a permanent internal hardware failure.

1. 1

   Park machine and remove key

   Park the machine on a level surface, turn off the engine, and remove the key.

2. 2

   Disconnect battery

   Disconnect the machine's battery, starting with the negative (-) cable, to prevent electrical arcing or further module damage.

3. 3

   Locate ECU

   Locate the Engine Control Unit (ECU) on the engine block or firewall (location varies by machine model).

4. 4

   Disconnect ECU wiring harness

   Carefully release the locking tabs and disconnect the main wiring harness connectors from the ECU.

5. 5

   Remove faulty ECU

   Unbolt the mounting hardware securing the ECU to its bracket and remove the faulty module.

6. 6

   Install replacement ECU

   Install the replacement ECU and tighten the mounting bolts securely.

7. 7

   Reconnect wiring harness

   Reconnect the wiring harness connectors, ensuring the locking levers are fully seated and latched.

8. 8

   Reconnect battery

   Reconnect the battery cables (positive first, then negative).

9. 9

   Program new ECU

   A new or remanufactured ECU will be blank or lack the specific machine's dataset. A certified technician must connect the Case IH EST laptop to flash the ECU with the correct software and calibration files for your specific VIN/PIN.

10. 10

    Clear codes and verify repair

    Clear any residual fault codes and run the engine to verify the repair.