Case IH 3740 (DTC E23D) - ECU – Engine Control Unit (ECU): ECU internal failure - ECU shutdown test failure

Internal failure within the Electronic Diesel Control (EDC) related to the injector power stages. The system detects an anomaly during the internal EDC shutdown test or undervoltage monitoring.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• AFX8010
• Steiger
• Magnum (180-240 CVT)
• Maxxum
• Farmall
• 115U Pro EP
• 105N
• 110C
• Luxxum series
• Case CE Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR/SV series
• TR/TV series
• 580 series Backhoe Loaders

1. 1

   Verify battery and charging system voltage is stable, as high voltage fluctuations or severe undervoltage can trigger internal ECU power stage faults.

2. 2

   Inspect the main engine wiring harness and the injector harness for short circuits (low side to battery or high side to ground).

3. 3

   Verify the main power relay to the EDC is not sticking or failing under load, which can disrupt the shutdown test.

4. 4

   Clear the code using the Electronic Service Tool (EST) and retest. If the code returns immediately upon key-cycle or engine shutdown, the internal failure is a hard fault within the EDC.

1. 1

   Disconnect battery

   Disconnect the machine's battery (negative terminal first) to prevent electrical arcing.

2. 2

   Locate ECU

   Locate the EDC/ECU on the engine block or firewall (location varies by chassis).

3. 3

   Disconnect harnesses

   Carefully release the locking levers on the 60-pin/94-pin main harness connectors and unplug them from the EDC.

4. 4

   Remove ECU

   Unbolt the EDC from its mounting bracket and remove it from the machine.

5. 5

   Install new ECU

   Install the new EDC and torque the mounting bolts to OEM spec.

6. 6

   Reconnect harnesses

   Reconnect the main wiring harnesses, ensuring the locking levers are fully seated.

7. 7

   Reconnect battery

   Reconnect the battery.

8. 8

   Program ECU

   Connect the Case IH Electronic Service Tool (EST). Flash the correct engine software dataset for your specific PIN/serial number and perform the injector trim code programming and self-learning routines.