New Holland ENG 3745 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): EDC - Power stages, Injector: Diagnostic fault check to report that WDA is not working correct

An internal hardware or software monitoring failure within the engine's computer where the ECU detects that the watchdog timer (WDA) for the fuel injector power stages is failing to communicate, timing out, or detecting an internal overvoltage/undervoltage condition. The ECU cannot guarantee the safe and correct firing of the fuel injectors.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Workmaster
• T4 series

1. 1

   Check for accompanying active injector-related fault codes (e.g., open/short circuits on specific cylinders) which can trip the power stage safety monitor.

2. 2

   Check battery voltage and charging system for severe undervoltage (<5V) or overvoltage spikes.

3. 3

   Inspect the engine wiring harness for short circuits to ground or power, and ensure ECU ground connections are clean, tight, and free of corrosion.

4. 4

   Clear the error code, cycle the ignition key OFF, wait for the ECU to complete its power-down cycle, and turn the ignition back ON to see if the code returns.

1. 1

   Connect diagnostic scan tool

   Connect a diagnostic scan tool (such as the CNH Electronic Service Tool - EST) and document all active and stored fault codes.

2. 2

   Inspect ECU connectors

   Perform a visual inspection of the ECU connectors. Look for water intrusion, bent pins, or corrosion, which can cause internal board shorts.

3. 3

   Verify power and ground feeds

   Verify the main power and ground feeds to the EDC module using a multimeter under load.

4. 4

   Clear fault code

   Clear the fault code (ENG 3745) with the diagnostic tool.

5. 5

   Cycle ignition

   Turn the ignition OFF and wait for the ECU to complete its after-run cycle, then turn the ignition back ON.

6. 6

   Check if code returns

   If the code immediately returns as active, the ECU has suffered an internal hardware failure in the watchdog/power stage circuitry.

7. 7

   Disconnect battery

   Disconnect the battery negative cable.

8. 8

   Replace ECU

   Remove and replace the Engine Control Unit (ECU/EDC).

9. 9

   Program new ECU

   Program/flash the new ECU with the correct software dataset for the specific machine using the CNH EST tool. You will also need to input the existing fuel injector trim codes (IQA codes) into the new module.