Case IH 19526 – Engine Control Unit (ECU): Short circuit to Ground on the output power stage

The control module has detected that the electrical circuit supplying power to the low-temperature coolant pump has shorted to a ground source. This is typically caused by damaged wiring touching the machine's chassis, a failed relay, or an internal short circuit within the coolant pump actuator itself.

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

1. 1

   Visually inspect the wiring harness from the Engine ECU to the Low Temperature Coolant Pump actuator for chafed insulation, pinched wires, or rubbing against the engine block or frame.

2. 2

   Disconnect the plug at the coolant pump (Connector C172) and inspect for moisture, corrosion, or melted pins.

3. 3

   Using a multimeter, test the pins on the coolant pump actuator for continuity to the pump housing, which would indicate an internal short.

4. 4

   Test the associated relays and fuses for the engine cooling system to ensure a relay hasn't failed internally and shorted to ground.

1. 1

   Disconnect power

   Turn off the machine and disconnect the negative battery cable to prevent further electrical damage or accidental shorts.

2. 2

   Isolate the fault

   Based on the diagnostic checks, determine if the short is located in the wiring harness or the pump actuator itself.

3. 3

   Repair wiring harness

   If the harness is damaged, splice and repair the broken or shorted wire using weather-sealed heat-shrink connectors, or replace the damaged connector pigtail.

4. 4

   Replace coolant pump

   If the pump has an internal short, drain the low-temperature coolant circuit into a clean drain pan. Disconnect electrical connector C172, remove coolant hoses, and unbolt the defective pump. Install the new pump, torque mounting bolts to OEM spec, and reconnect hoses.

5. 5

   Reassemble and bleed system

   Reconnect the electrical plug and refill the low-temperature cooling circuit with the specified OEM coolant.

6. 6

   Clear codes and test

   Reconnect the battery, use a diagnostic scan tool to clear fault code 19526 from the Engine ECU, and run the engine to verify the pump operates without triggering the code.