Case IH 17590 (F-518408-03) - ECU – Engine Control Module (ECM): Power Relay driver is short circuit to battery only

The control circuit responsible for activating the power relay is inappropriately receiving battery voltage, indicating a short to a 12V power source somewhere in the circuit.

• VESTRUM CVX
• Maxxum
• Puma
• Optum
• Farmall

1. 1

   Locate the main engine power relay and the ECM.

2. 2

   Disconnect the power relay and use a multimeter to check the relay driver circuit (the wire running from the ECM to the relay coil) for voltage. If battery voltage is present when the circuit should be unpowered, a short to battery exists.

3. 3

   Inspect the wiring harness between the ECM and the power relay for chafed insulation, melted wires, or pinches that could cause the driver wire to touch a constant or switched battery power wire.

4. 4

   Inspect the ECM connector pins and the relay socket for corrosion, bridging, or damage.

5. 5

   Test the power relay itself for internal shorts between the power contacts and the coil circuit.

1. 1

   Disconnect the negative battery cable before performing any electrical repairs.

2. 2

   If the wiring harness is damaged and shorting to power, isolate the affected section.

   Cut out the damaged wire and splice in a new section using weather-sealed connectors, or replace the affected harness section entirely.

3. 3

   If the power relay is internally shorted, remove the faulty relay from the fuse/relay block and install a new OEM replacement relay.

4. 4

   Reconnect the battery.

5. 5

   Use a CNH Electronic Service Tool (EST) or compatible diagnostic scanner to clear the inactive fault code 17590 from the ECM memory.

6. 6

   Cycle the ignition key and start the engine to verify the fault code does not return and the power relay functions correctly.