New Holland ENG 3972 – Engine Control Unit (ECU): Intake Throttle Motor Driver Circuit Invalid

This indicates an electrical fault—such as a short, open circuit, or invalid signal—within the driver circuit that controls the intake throttle valve actuator motor.

• L180
• L216
• L218
• L220
• L228
• SR175
• SV185

1. 1

   Verify if any other fault codes are present. If no other codes are active, proceed with the throttle circuit diagnosis.

2. 2

   Inspect the wiring harness running from the Engine ECU to the intake throttle position sensor/motor connector for damage, corrosion, abrasion, and incorrect attachment.

3. 3

   Run the intake status and active test using the Service Diagnostics Tool.

4. 4

   Visually inspect the intake throttle valve. If it is stuck due to carbon buildup, it may require cleaning per the OEM 'Throttle Valve Actuator (TVA) - Cleaning (55.014)' procedure.

5. 5

   Check the supply and ground reference circuits for the motor.

1. 1

   Disconnect harness

   Disconnect the wiring harness from the Engine ECU and the intake throttle valve.

2. 2

   Test wiring harness

   Perform continuity and short-to-ground tests on the wiring harness to isolate the driver circuit.

3. 3

   Repair wiring harness

   If the wiring harness test fails (revealing breaks or shorts), locate and repair the damaged conductor or connector.

4. 4

   Replace intake throttle valve

   If the wiring harness tests good, the intake throttle valve sensor/motor has failed internally and the assembly must be replaced.

5. 5

   Reconnect harness

   After repairing the wiring or replacing the valve, reconnect the harness.

6. 6

   Verify repair

   Operate the machine while monitoring the display to ensure the error has been resolved and does not return.