Case IH 3750 (F-5441-02) – Engine Control Module (ECM / ECU): ECU internal failure - Fuel injection energizing time is not plausible

The engine's computer has detected an internal calculation or hardware error where the duration required to energize the fuel injectors does not align with expected or physically possible parameters.

• VESTRUM CVX
• Case IH 240 Series Axial-Flow® Combines
• Case IH Farmall 115U Efficient Power Tractors

1. 1

   Check for Voltage Drops: Verify the ECU power supply and ground connections. Look for accompanying codes like DTC 3763 (ECU 5 volt supply voltage is lower than expected), which indicates a voltage supply issue rather than a strictly internal failure.

2. 2

   Inspect Injector Wiring: Check the engine-to-ECU wiring harness and the specific fuel injector harnesses for shorts to ground or voltage. A shorted injector circuit can backfeed into the ECU and cause energizing time plausibility faults.

3. 3

   Check for Related Injector Codes: Look for related internal failure codes such as 3751 (Fuel injection energizing phase is not plausible), 3753 (Injection quantity correction), or 3754 (Rail pressure plausibility). If multiple internal failure codes are present and wiring is intact, the ECU itself has failed.

1. 1

   Power Down

   Turn off the machine and disconnect the battery cables to prevent electrical arcing.

2. 2

   Locate the ECU

   The Engine Control Module is typically assembled directly to the engine block via a heat exchanger (cooling plate) and utilizes rubber buffers to reduce engine vibration.

3. 3

   Disconnect Harnesses

   Disconnect the tractor-to-engine harness connectors.

4. 4

   Remove ECU Connectors

   Disconnect the ECM connectors by moving the locking handles from the right (locked position) to the left (unlocked position).

5. 5

   Dismount the ECU

   Unbolt the ECU from its rubber isolation buffers/heat exchanger bracket.

6. 6

   Install the New ECU

   Mount the replacement ECU, ensuring the vibration buffers are intact. Reconnect the locking harness connectors.

7. 7

   Reprogramming

   A new ECU will require programming/flashing by an authorized Case IH dealer using their proprietary diagnostic software to match the specific engine and machine configuration.