Case IH 3671 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): EGR Valve Circuit - Short Circuit To Ground (A = 60pin Connector - Engine; A50)

The engine controller has detected a short circuit to ground on the output circuit (Out1 / Pin A50) that drives the Exhaust Gas Recirculation (EGR) valve's H-bridge actuator. This means the electrical current intended to control the EGR valve is bypassing the component and going directly to the chassis ground, preventing the valve from operating.

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1. 1

   Inspect the engine wiring harness between the EGR valve and the Engine ECU (specifically tracing the wire from Pin A50 on the 60-pin connector) for chafed insulation, pinched wires, or melted loom.

2. 2

   Disconnect the EGR valve and the 60-pin ECU connector to check for water ingress, corrosion, or bent pins.

3. 3

   Measure continuity between the Pin A50 wire and chassis ground using a multimeter with both ends disconnected.

4. 4

   Test the EGR valve actuator internally for a short to ground if the harness is clear.

5. 5

   Verify if the short is internal to the ECU's H-bridge driver if the harness and valve test fine.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal before servicing ECU wiring or engine sensors.

2. 2

   Repair/Replace Wiring

   If a short was found in the harness during diagnostics, repair the damaged wire section or replace the engine harness.

3. 3

   Replace EGR Valve

   Remove the fastening screws securing the EGR valve to the intake manifold. Disconnect the EGR pipe from the valve housing by loosening the retaining clips. Remove the faulty EGR valve and install the new unit, torquing the front side and valve support screws to OEM specification. Reconnect the EGR piping and electrical connector.

4. 4

   ECU Reset / Calibration

   After replacing the EGR valve, you must use a diagnostic service tool (such as CNH EST, Jaltest, or TEXA) to reset the self-learning parameters. Navigate to the engine module and select “Replacement of the EGR valve – Reset ECU Data” and execute the reset.