Case IH 3671 – Engine Control Unit (ECU): EGR Valve Circuit - Short Circuit To Ground on Out1 error for H-bridge

The engine control module has detected a short circuit to ground on the circuit that controls the Exhaust Gas Recirculation (EGR) valve motor. The Out1 circuit traces to Pin A50 on the 60-pin Engine Connector.

• Farmall
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Inspect the engine wiring harness between the Engine ECU and the EGR valve for chafed, melted, or pinched wires that could be grounding out.

2. 2

   Disconnect the 60-pin connector at the Engine ECU and the connector at the EGR valve, then test the wire corresponding to ECU Pin A50 for continuity to ground using a digital multimeter.

3. 3

   If the wiring harness tests good (no short to ground), suspect an internal short circuit within the EGR valve's H-bridge actuator motor.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable.

2. 2

   Address Wiring

   If diagnostic tests revealed a short in the harness, locate the damaged section. Repair the wire using proper weather-sealed connectors, or replace the engine wiring harness if the damage is extensive.

3. 3

   Replace the EGR Valve

   If the wiring is intact and the short is internal to the actuator: Disconnect the electrical connector from the EGR valve. Remove the mounting hardware securing the EGR valve to the exhaust/intake manifold. Remove the faulty EGR valve and clean the mating surfaces. Install the new EGR valve with a new gasket and torque the bolts to OEM specifications.

4. 4

   Reassembly

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

5. 5

   Software Reset

   Connect the Case IH Electronic Service Tool (EST). Clear the inactive fault codes. Depending on the exact model, you may need to run a routine to reset the ECU data so it can perform self-learning parameters for the new EGR valve position.

6. 6

   Verification

   Start the engine, allow it to reach operating temperature, and verify that fault code 3671 does not return.