New Holland ENG 3958 – ISM-DI ENGINE: COM1 Output Open Load Both TWV1 and TWV3 Open Load

Indicates an open circuit condition (such as a broken wire, disconnected plug, or burnt-out internal coil) on the common circuit 1 (COM1) that controls the Two-Way Valves (TWV) for fuel injectors 1 and 3.

• L218
• L220
• C175
• SR160
• SR175
• SV185

1. 1

   Inspect the engine wiring harness between the Engine ECU and the fuel injectors (specifically cylinders 1 and 3) for any chafing, breaks, or loose connections

2. 2

   Verify that the electrical connectors on injector 1 (TWV1) and injector 3 (TWV3) are securely plugged in

3. 3

   Measure the resistance of the injector coils for cylinders 1 and 3 using a multimeter to check for an internal open circuit (infinite resistance)

1. 1

   Ensure the machine is turned off and the battery is disconnected before servicing the fuel system or ECU wiring.

2. 2

   Reconnect any loose or disconnected injector plugs found during the diagnostic phase.

3. 3

   If the wiring harness is damaged or broken on the COM1 circuit, repair the broken wires or replace the injector wiring harness section.

4. 4

   If the diagnostic tests reveal an open circuit inside the injector coil itself, the faulty fuel injector must be replaced.

   Service guidelines often recommend replacing the entire set of fuel injectors to ensure optimal engine performance and to avoid mixing parts with different atomization concentrations.

5. 5

   Clear the DTC (Diagnostic Trouble Code) from the engine ECU using a diagnostic tool or DTC eraser.