Case IH 3672 – Engine ECU (Engine Controller): EGR Valve Circuit - Short Circuit To Ground

The engine controller has detected a short to ground on the EGR Out2 circuit, which corresponds to pin A35 on the 60-pin engine connector (Connector A). This means the electrical signal controlling the Exhaust Gas Recirculation (EGR) valve is grounding out before it can properly actuate the valve, or the valve's internal circuitry has failed and shorted to ground.

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1. 1

   Visual Inspection: Inspect the wiring harness running from the Engine ECU to the EGR valve. Look for chafed insulation, pinched wires, or areas where the harness might be rubbing against the engine block or exhaust components, causing a short to ground.

2. 2

   Connector Check: Disconnect the 60-pin connector (Connector A) at the Engine ECU and the connector at the EGR valve. Inspect both for water intrusion, corrosion, or bent pins.

3. 3

   Harness Continuity Test: With both ends disconnected, use a multimeter to test for continuity between pin A35 on the engine harness and a known good chassis ground. If there is continuity, the wiring harness is shorted to ground. If there is no continuity, the harness is good, and the short is likely internal to the EGR valve actuator itself.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical damage.

2. 2

   Harness Repair (If Applicable)

   If the diagnostic test revealed a short in the wiring, trace the wire from pin A35, locate the damaged section, and repair it using proper weather-sealed splices, or replace the engine wiring harness.

3. 3

   EGR Valve Replacement (If Applicable)

   If the harness tested good, the EGR valve is internally shorted. Disconnect the electrical connector from the EGR valve.

4. 4

   Remove mounting hardware

   Remove the mounting hardware securing the EGR valve to the exhaust/intake manifold.

5. 5

   Remove faulty EGR valve

   Remove the faulty EGR valve and thoroughly clean the mounting surface.

6. 6

   Install new EGR valve

   Install the new EGR valve using a new gasket and torque the mounting bolts to OEM specifications.

7. 7

   Reconnect connectors

   Reconnect the EGR valve electrical connector and the 60-pin Engine ECU connector.

8. 8

   Reconnect battery

   Reconnect the negative battery cable.

9. 9

   Calibration

   Connect a diagnostic service tool to the machine and clear the fault codes. You must follow the appropriate service tool procedure to restore self-learning parameters and calibrate the new EGR valve to the engine control unit. Failure to do so may result in poor performance or returning fault codes.