New Holland ENG 3821 – Engine Control Unit (ECU): Throttle Valve Actuator (TVA) Circuit - Short Circuit To Battery on Out1 error for H-bridge (Pin A49)

This code indicates that the Engine Control Unit (ECU) has detected a short circuit to an external power source (positive battery voltage) on the Throttle Valve Actuator drive circuit. Specifically, the short is registered on the "Out1" circuit of the H-bridge, which corresponds to Pin A49 on the 60-pin engine connector.

• L220
• L465
• LX465
• LX485
• SR175
• B90B
• B100B
• F5C engines
• F5H engines

1. 1

   Verify the fault code is currently active on the machine's display

2. 2

   Inspect the Throttle Valve Actuator connector (X-016) to ensure it is secure, tight, and completely free of corrosion, moisture, abrasion, or bent pins

3. 3

   Trace the wiring harness from the TVA back to the 60-pin Engine ECU connector, checking for rubbed-through wire insulation shorting to a positive battery source (pay special attention to the wire leading to Pin A49)

4. 4

   Inspect the Throttle Valve Actuator mechanically to ensure the internal valve is not jammed, sticking, or clogged with soot/carbon buildup

5. 5

   If the wiring harness tests perfectly for continuity and lacks shorts, and the TVA operates freely, verify if the ECU itself has an internal short on the H-bridge driver

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery terminal before servicing the electrical system.

2. 2

   Repair Wiring

   If the diagnostic checks reveal a short to battery voltage in the harness, repair the damaged section of the wire leading to ECU Pin A49, or replace the engine wiring harness entirely.

3. 3

   Clean or Replace the TVA

   If the TVA valve is jammed or sticking due to carbon buildup, attempt to clean it using an approved intake/EGR cleaner. If the actuator motor is internally shorted or the valve remains stuck after cleaning, unbolt the TVA from the intake tube, disconnect the electrical pigtail, and install a new Throttle Valve Actuator. Torque the mounting bolts to 20 - 30 N·m (15 - 22 lb ft).

4. 4

   ECU Replacement

   If the wiring is intact and the TVA is functioning properly, the Engine ECU has a faulty internal H-bridge driver. The ECU will need to be replaced and reprogrammed by an authorized New Holland dealer.

5. 5

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic tool to clear the inactive fault codes. Run the engine to verify the code does not return.