New Holland ENG 3986 – Engine Control Unit (ECU) / ISM-IDI ENGINE: Linear Solenoid: High Current

The Engine Control Unit (ECU) has detected an abnormally high electrical current draw on the circuit that controls the linear solenoid. This typically indicates a short circuit to ground in the wiring harness or an internal short within the solenoid coil itself.

• L213
• L216
• L218
• L220
• L230
• C238
• SR130
• SR160
• SR175
• SV185
• SR210
• SR240
• SV280
• TR270

1. 1

   Inspect the wiring harness running from the Engine ECU to the fuel injection pump linear solenoid for chafed wires, melted insulation, or pinch points.

2. 2

   Disconnect the linear solenoid and the rack position sensor connectors to check for water intrusion, corrosion, or bent/pushed-out pins.

3. 3

   With the battery disconnected and the ECU unplugged, use a multimeter to check the linear solenoid control wire for continuity to ground (continuity indicates a shorted harness).

4. 4

   Measure the resistance (Ohms) across the pins of the linear solenoid itself. A reading near 0 ohms indicates an internal short requiring replacement.

1. 1

   Prep the Machine

   Park the machine on a level surface, lower the boom, turn off the engine, and disconnect the negative battery cable.

2. 2

   Access the Injection Pump

   Locate the fuel injection pump on the side of the ISM-IDI engine. Clean the area around the pump thoroughly to prevent dirt from entering the fuel system.

3. 3

   Disconnect Electronics

   Unplug the electrical connector leading to the linear solenoid/rack actuator.

4. 4

   Remove the Solenoid

   Unbolt the linear solenoid assembly from the fuel injection pump housing.

5. 5

   Install the New Solenoid

   Lubricate the O-ring seals on the new linear solenoid with clean engine oil before inserting it into the seat to prevent twisting or tearing. Carefully position the solenoid and torque the mounting bolts to OEM specifications.

6. 6

   Reassembly

   Reconnect the electrical connector to the solenoid.

7. 7

   Bleed the System

   If the fuel system was opened or drained during the process, remove air from the engine fuel lines by priming the system.

8. 8

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use the Electronic Service Tool (EST) to clear the inactive 3986 fault code. Start the engine and verify the code does not return.