Case IH 19522 – Engine Control Unit (ECU): Low Temperature Coolant Pump actuator - Short circuit to Ground on the output power stage

This fault indicates that the engine's control module has detected a short circuit to ground in the electrical circuit that controls the Low Temperature Coolant Pump actuator. The "output power stage" refers to the internal driver within the control module that sends voltage to the pump actuator. A short to ground means the wiring is touching the chassis/ground, or the actuator itself has suffered an internal electrical short, causing an excessive current draw that the module has disabled to protect the circuit.

• Tier 4b
• Case IH Steiger
• Case IH Magnum

1. 1

   Visual Inspection: Inspect the wiring harness running from the Engine ECU to the Low Temperature Coolant Pump actuator. Look for chafed insulation, melted wires, or pinch points where the wire might be shorting against the engine block or chassis.

2. 2

   Harness Isolation Test: Disconnect the electrical connector at the Low Temperature Coolant Pump actuator. Use a multimeter to check for continuity to ground on the power supply wire. If there is continuity to ground while unplugged, the wiring harness is shorted and needs repair.

3. 3

   Actuator Internal Short Test: If the harness tests fine, test the pins on the Low Temperature Coolant Pump actuator itself. An internal short in the pump's electrical motor/actuator is a common cause for this code.

4. 4

   ECU Pin Check: Inspect the ECU connector pins for corrosion, water ingress, or bent pins that could be bridging the circuit to a ground pin.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery via the master disconnect switch to prevent electrical arcing.

2. 2

   Access the Pump

   Locate the Low Temperature Coolant Pump, which is typically mounted near the cooling package/intercooler circuit on the engine.

3. 3

   Wiring Repair (If Applicable)

   If the diagnostic checks revealed a shorted wire, splice in a new section of wire using weather-sealed heat-shrink connectors, or replace the affected harness section.

4. 4

   Replace the Actuator/Pump (If Applicable)

   Drain the low-temperature coolant circuit into a clean drain pan. Disconnect the electrical connector (e.g., C171 or C172) from the pump. Remove the mounting bolts and hose clamps securing the pump. Install the new Low Temperature Coolant Pump actuator. Reconnect the hoses and torque the mounting bolts to OEM spec.

5. 5

   Refill and Bleed

   Refill the low-temperature coolant circuit. It is absolutely essential that the low-temperature circuit is filled and bled without air bubbles to ensure proper charge-air cooling.

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 pump operates and the code does not return.