New Holland ENG 3671 – Engine ECU: EGR Short to Ground on EGR Out1 pin A50 error for H-bridge

The engine control system has detected a short circuit to ground on the output circuit 1 that controls the Exhaust Gas Recirculation (EGR) valve's H-bridge motor driver. The short is specifically traced to pin A50 on the 60-pin engine connector.

• L220
• L225
• L230
• SR175
• C232
• C238
• B90B
• B95C
• B100B
• B110C
• U80C

1. 1

   Inspect the wiring harness running from the Engine ECU to the EGR valve for chafing, melted insulation, or pinched wires that could cause a short to ground.

2. 2

   Inspect the 60-pin connector at the Engine ECU and the connector at the EGR valve to ensure they are secure, tight, and free of corrosion, moisture, or bent pins.

3. 3

   Disconnect the harness from both the ECU and the EGR valve. Using a multimeter, test the wire corresponding to ECU pin A50 for continuity to ground to verify if the harness is shorted.

4. 4

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

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical damage during the repair.

2. 2

   Repair or replace wiring harness

   If the diagnostic tests revealed a shorted harness, repair the damaged section of the wire leading to pin A50, or replace the engine wiring harness entirely.

3. 3

   Remove faulty EGR valve

   If the harness is intact, the EGR valve has failed internally. Unbolt and remove the faulty EGR valve assembly from the engine.

4. 4

   Install new EGR valve

   Clean the mounting surface and install the new EGR valve with a new gasket.

5. 5

   Reconnect components

   Reconnect the EGR valve harness, the 60-pin ECU connector, and the battery.

6. 6

   Connect diagnostic tool

   Connect the New Holland Electronic Service Tool (EST) to the machine's diagnostic port.

7. 7

   Restore Self Learning Parameters

   Because the EGR valve is an electronically controlled and monitored component, you must use the service tool to run the 'Restore Self Learning Parameters' procedure. This allows the Engine ECU to learn the end-stops and resistance of the new EGR valve.

8. 8

   Clear codes and verify

   Clear the inactive fault codes and run the engine to verify the code does not return.