New Holland ENG 3818 – Engine Control Unit (ECU) / EDC: EDC: Open load error for power stage / Throttle Valve Actuator (TVA) Circuit - Open Load Error For Power Stage

The engine controller has detected an open electrical circuit (a break in the wiring, a disconnected plug, or an internal break in the actuator motor) in the H-bridge drive circuit that powers the Throttle Valve Actuator.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• L218 Tier 4
• Backhoe Loaders
• B95C
• B110C Tier 4B
• Tractors
• Workmaster 50

1. 1

   Visually inspect the intake throttle valve for sticking due to heavy soot or carbon buildup (may require cleaning procedure).

2. 2

   Check the supply and ground reference circuits by disconnecting the wiring harness from the intake throttle sensor and verifying voltage with the key switch in the ON position.

3. 3

   Inspect the wiring harness between the ECU and the TVA for broken wires, chafing, or loose connector pins that would cause an open load condition.

1. 1

   Disconnect electrical connections

   Disconnect the electrical connections to the Throttle Valve Actuator (TVA) and the adjacent air pressure/temperature sensor.

2. 2

   Remove intake tube

   Remove the intake tube.

3. 3

   Remove hardware

   Remove the bolts and nuts securing the TVA.

4. 4

   Install new TVA

   Install the new Throttle Valve Actuator (TVA) and reinstall the intake tube.

5. 5

   Torque hardware

   Torque the mounting bolts and nuts to 20 - 30 N·m (15 - 22 lb ft).

6. 6

   Reconnect electrical connections

   Reconnect the electrical connections to the TVA and the air pressure/temperature sensor.

7. 7

   Perform post-repair calibration

   If the fault persists and the EDC/ECU itself must be replaced due to an internal power stage failure, you must follow the appropriate service tool procedure to restore the engine's self-learning parameters.