New Holland ENG 3747 – EDC (Electronic Diesel Control): EDC - Power stages, Injector: Diagnostic fault check to report that the positive test failed

The engine controller actively monitors the electrical circuits that supply power to the fuel injectors. This code indicates that the diagnostic check on the "positive" side of the injector power stage has failed. This means the controller has detected an electrical fault—such as a short circuit, an open circuit, or an internal processing error within the controller's own injector power delivery circuitry.

• Machines equipped with the F5C Engine (Skid Steer Loaders and Compact Track Loaders)
• CR9090 Combine
• CX8080 Elevation Combine
• CX8090 Elevation Tier 4A Combine
• T6 series Tractor
• T7 series Tractor
• T8 series Tractor
• T9 series Tractor
• Boomer series Tractor

1. 1

   Visually inspect the engine wiring harness connecting the EDC to the fuel injectors for chafing, melting, or corrosion

2. 2

   Disconnect the harness and use a multimeter to test the injector circuits for continuity, short-to-ground, and short-to-battery (specifically focusing on the positive/high side of the circuit)

3. 3

   Test the resistance of the fuel injectors to ensure an internally shorted injector is not causing the EDC power stage to fail the diagnostic test

4. 4

   Check for a software or processing error during the ECU startup phase

1. 1

   Verify Wiring

   If the diagnostic checks reveal a short or open circuit in the wiring harness or a faulty injector, repair the wiring or replace the affected injector. Clear the codes and retest.

2. 2

   Flash the ECU

   If the wiring and injectors test perfectly, the Engine Control Unit (ECU) has detected a processing error during ECU start up. Try to flash the ECU correctly with the proper data set using the New Holland Electronic Service Tool (EST) to reload the engine dataset/software.

3. 3

   Replace the EDC

   If the error persists after flashing the controller, the internal injector power stages of the EDC are permanently damaged. You must replace the Engine Controller (EDC).

4. 4

   Restore Parameters

   If the EDC is replaced, you must follow the appropriate service tool procedure to restore the engine's self-learning parameters (such as injector calibration codes and zero fuel calibration).