Case IH 3507 (DTC 4761) - ECU – Engine ECU: Engine cranked for too long or key switch failure

This condition occurs when the control system detects that the starter motor has been engaged for an excessive duration (typically over 30 seconds) without the engine successfully starting, or it detects an electrical fault/sticking mechanism within the ignition key switch that is sending a continuous crank signal.

• MAXXUM T4E
• 240 Series Axial-Flow Combines

1. 1

   Verify Operator Error vs. Mechanical Failure: Determine if the engine was simply cranked for more than 30 seconds due to a hard-start condition (e.g., fuel starvation, cold weather, or loss of prime).

2. 2

   Inspect the Key Switch: Check the ignition key switch for physical damage, sticking, or a loose feeling when turning. Ensure the key springs back from the "Start" position to the "Run" position automatically.

3. 3

   Electrical Testing: Use a multimeter to test the key switch terminals for proper continuity in the "Start" and "Run" positions.

4. 4

   Check the Starter Circuit: Inspect the starter relay and wiring harness for shorts to power that might be causing a continuous crank signal even when the key is released.

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent accidental cranking or electrical shorts during the repair.

2. 2

   Access the Switch

   Remove the dash panel, steering column cover, or operator control console panel to access the back of the ignition switch.

3. 3

   Disconnect Wiring

   Disconnect the wiring harness from the back of the key switch. It is highly recommended to mark the wires or take a photo before removal to ensure correct reinstallation.

4. 4

   Remove the Old Switch

   Remove the retaining nut holding the switch to the panel and pull the old switch out.

5. 5

   Install the New Switch

   Insert the new ignition key switch into the panel and secure it tightly with the retaining nut.

6. 6

   Reconnect Wiring

   Reconnect the wiring harness to the appropriate threaded screw or spade terminals on the new switch.

7. 7

   Test the System

   Reconnect the battery. Turn the key to verify that the electrical system powers on, the starter engages properly in the "Start" position, and the starter disengages immediately when the key is released. Clear the fault code from the ECU.