Case IH 3825 – Engine Control Unit (ECU): Throttle Valve Actuator (TVA) Circuit - Short Circuit Over Load Error For H-Bridge

The ECU has detected an excessive current draw (an overload) on the H-bridge circuit. This is almost always caused by a dead short inside the TVA motor itself, or a severe short-to-ground/short-to-power in the wiring harness between the ECU and the TVA.

• Farmall
• skid steer
• Farmall 75C
• Farmall 95U
• Farmall 105U
• Farmall 115U Pro EP
• Maxxum
• Puma
• SR175
• SV300
• TR270
• TR320
• TV380

1. 1

   Inspect the wiring harness running from the Engine ECU (specifically the 60-pin engine connector, pins A34 and A49, which supply the TVA) to the Throttle Valve Actuator for melted insulation, chafing against engine brackets, or pinched wires.

2. 2

   Disconnect the electrical connector at the TVA and use a digital multimeter to measure the resistance across the motor power pins; a reading of near 0 ohms indicates a dead internal short in the actuator motor.

3. 3

   With the TVA and battery disconnected, test the harness side of the connector for continuity to ground and continuity between the power wires to identify a harness short.

4. 4

   Check the TVA and ECU connectors for water intrusion, corrosion, or bent pins that could be bridging the circuit.

1. 1

   Turn off the machine, remove the key, and disconnect the negative battery cable to protect the ECU.

2. 2

   Locate the Throttle Valve Actuator on the engine intake piping (typically situated between the turbocharger intercooler outlet and the intake manifold).

3. 3

   Disconnect the electrical harness connector from the TVA.

4. 4

   Loosen the hose clamps or remove the mounting bolts securing the TVA to the intake manifold and intercooler piping.

5. 5

   Remove the faulty TVA. Thoroughly clean the mating surfaces on the intake piping to ensure a proper seal.

6. 6

   Install the new Throttle Valve Actuator using new gaskets/O-rings.

7. 7

   Reattach the intake piping and tighten the clamps/bolts securely.

   Standard torque for F5C intake/exhaust components is generally 10 - 20 Nm, but avoid overtightening plastic or thin-walled aluminum components.

8. 8

   Reconnect the electrical harness to the new TVA.

9. 9

   Reconnect the battery. Turn the key to the ON position and use a diagnostic tool (such as the CNH Electronic Service Tool) to clear the inactive 3825 fault code.

   The ECU may require a key cycle to relearn the new valve's end-stops.