Case IH 19594 – Engine Control Module (ECM) / Engine Control Unit (ECU): ECU power stage hardware reports a 'no load' error.

A 'power stage' is an internal driver circuit within the control module responsible for supplying voltage/ground to external components. A 'no load' error means the module is trying to send power to a circuit but is detecting infinite resistance (an open circuit). The module expects to see a specific electrical load (resistance) from the component, and its absence triggers this hardware fault.

• Tier 4b
• Puma
• Optum
• Magnum
• Steiger
• N-Series Tractor Loader Backhoes (TLBs)
• T7 Series

1. 1

   Scan for Sub-Codes using the CNH Electronic Service Tool (EST) to read freeze-frame data or secondary fault codes to identify the specific component circuit.

2. 2

   Inspect the main engine wiring harnesses connecting to the ECM for disconnected plugs, backed-out pins, corrosion, or chafed wires that would cause an open circuit.

3. 3

   Verify all fuses and relays providing power to the engine actuators and the ECM (a blown fuse on the load side will cause a 'no load' reading).

4. 4

   Use a multimeter to measure the resistance of the identified actuator/component to check if it reads out of limits (O.L.), indicating it has failed open.

1. 1

   Isolate the Circuit

   Using the diagnostic tool, identify the open circuit.

2. 2

   Repair Wiring/Component

   If a wire is broken, repair the harness using OEM-approved splicing methods. If the actuator/component tests open (infinite resistance), replace the component.

3. 3

   Test the ECM

   If the wiring harness tests perfectly (continuity from the ECM pin to the component and good ground) and the component is functional, the internal power stage driver within the ECM has burned out.

4. 4

   Replace the ECM (if necessary)

   Disconnect the battery. Remove the faulty ECM. Install the new ECM and flash/program it with the correct dataset for the machine using the CNH EST.

5. 5

   Clear and Verify

   Clear the fault codes, cycle the key, and run the engine under load to verify the code does not return.