Case IH 19667 – Engine Control Unit (ECU): ECU Powerstage for pre-supply pump: open load of output

The Engine Control Unit (ECU) has detected an "open load" (an open electrical circuit) on the output line that supplies power to the pre-supply fuel pump (also known as the low-pressure fuel lift pump or transfer pump). This condition is typically caused by a disconnected plug, a broken wire in the harness, or a burnt-out internal motor winding inside the pump itself.

• Tier 4b
• Case 580N
• Case 580SN (Super N)
• Case 580SN WT
• Case 590SN

1. 1

   Visually inspect the pre-supply fuel pump electrical connector for disconnected plugs, backed-out pins, or heavy corrosion.

2. 2

   Using a multimeter, check the wiring harness between the ECU and the pre-supply pump for continuity, looking for chafed or broken wires along the frame rail.

3. 3

   Disconnect the harness from the pre-supply pump and measure the resistance across the pump's electrical terminals. An 'OL' (open line) reading indicates a failed internal motor.

1. 1

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the pre-supply fuel pump (fuel transfer pump), which is typically mounted in-line near the primary fuel filter assembly.

3. 3

   Disconnect the electrical harness connector from the pump.

4. 4

   Place a drain pan underneath the pump to catch residual diesel fuel.

5. 5

   Disconnect the fuel inlet and outlet lines from the pump.

6. 6

   Remove the mounting hardware securing the pump to the bracket and remove the faulty unit.

7. 7

   Install the new pre-supply pump and secure the mounting bolts.

8. 8

   Reconnect the fuel lines, ensuring any O-rings or sealing washers are properly seated to prevent air leaks.

9. 9

   Reconnect the electrical harness to the new pump.

10. 10

    Reconnect the battery. Turn the ignition key to the "ON" position (without starting the engine) to allow the new pump to prime the fuel system. Check for any fuel leaks at the fittings.

11. 11

    Connect a diagnostic scan tool to clear the 19667 fault code from the ECU.