Case IH 19642 – Engine Control Unit (ECU / EDC) or Transmission Control Unit (TCU): Short circuit to battery of the pressure control valve output.

The Engine Control Module (ECM) or Transmission Control Unit (TCU) has detected that the electrical circuit controlling the pressure control valve (often the fuel high-pressure pump metering unit/MPROP or a transmission hydraulic valve) has a short to a high voltage source. This means voltage from the battery is bleeding into the valve's control circuit (either the high side or low side power stage) without being commanded by the ECU, which prevents the module from regulating pressure properly.

• Tier 4b
• Case IH tractors and combines utilizing Bosch EDC systems or EEM4 engine management systems
• Tier 3 FPT engines
• Tier 4 FPT engines

1. 1

   Verify the Fault: Check if the fault is currently active using an Electronic Service Tool (EST).

2. 2

   Visual Inspection: Inspect the wiring harness leading to the pressure control valve for chafing, melted insulation, or pinched wires that could cause a short to a 12V power source.

3. 3

   Connector Check: Disconnect the pressure control valve (MPROP) and inspect the connector pins for corrosion, moisture, or bent terminals.

4. 4

   Voltage/Short Test: With the valve disconnected and the key ON, measure the low side and high side of the wiring terminal to engine ground using a multimeter to see if there is an unintended short circuit to battery voltage.

5. 5

   Component Test: Plug the harness into a known-good (or spare) MPROP solenoid valve to see if the fault clears. If it does, the original solenoid valve is internally shorted.

1. 1

   Turn off the machine and disconnect the negative battery terminal

   This prevents further electrical damage.

2. 2

   Disconnect the wiring harness from the pressure control valve and the ECU.

3. 3

   Using a multimeter, perform a continuity test on the valve's signal and ground wires against the battery positive cable.

4. 4

   If a short is found in the harness, trace the wire back to the ECU.

   Repair the chafed/damaged section of the wire using OEM-approved heat-shrink connectors, or replace the affected harness section.

5. 5

   If the wiring harness tests perfectly, use a multimeter to test the internal resistance of the pressure control valve itself.

   If it is shorted internally, remove the retaining bolts, extract the faulty valve, and install a new pressure control valve.

6. 6

   Reconnect all harnesses and the battery.

7. 7

   Connect the Electronic Service Tool (EST), clear the inactive fault codes, and run the engine/machine to verify the repair.