Case IH 19204 – Engine Control Module (ECM / EDC): External Actuator Relay 1: Open Load error at low side power stage.

The Engine Control Module (ECM) hardware has monitored the power stage of External Actuator Relay 1 and detected an open circuit. This is typically caused by broken or disconnected wiring on the low side of the circuit, or an internal open circuit (failure) within the actuator connected to this relay.

• Tier 4b
• Case IH Puma series (115 through 180+)
• Case IH Magnum and Steiger tractors
• Case IH Maxxum series
• Various Case IH combines and self-propelled sprayers

1. 1

   Verify that the system battery voltage is within normal operating parameters, as low voltage can trigger false power stage errors.

2. 2

   Inspect the wiring harness connecting the ECM, External Actuator Relay 1, and the specific external actuator for chafed wires, disconnected plugs, or pushed-out pins.

3. 3

   Use a multimeter to check the continuity of the wiring on the low side power stage between the relay and the actuator.

4. 4

   Measure the internal resistance of the actuator connected to Relay 1 to verify if the open load is internal to the actuator itself.

5. 5

   Test the relay for proper switching operation and inspect the relay socket for corrosion or heat damage.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical shorts during testing.

2. 2

   Locate Components

   Locate External Actuator Relay 1 in the engine fuse/relay box and trace the harness to the connected external actuator.

3. 3

   Repair Wiring

   If the continuity test reveals a broken wire or damaged connector on the low side circuit, repair the wiring harness or replace the damaged connector pigtail.

4. 4

   Replace the Relay

   If the wiring is intact but the relay fails a bench test (or shows signs of internal failure/burnt contacts), replace the relay.

5. 5

   Replace the Actuator

   If the wiring and relay are both functioning properly, the open load is inside the actuator. Remove the defective actuator and install a new OEM replacement.

6. 6

   Clear Codes

   Reconnect the battery, connect the CNH Electronic Service Tool (EST), clear the inactive fault codes, and run the engine to verify the code does not return.