Case IH 3820 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Throttle Valve Actuator (TVA) Circuit - Over Temperature Error For H-Bridge

The H-bridge driver circuit within the engine control module has exceeded its maximum safe operating temperature. This overheating is almost always caused by excessive electrical current draw, commonly due to a mechanically binding throttle valve flap, a failing internal electric motor in the TVA, or a short circuit in the wiring harness.

• Farmall
• skid steer
• Farmall 115U Pro EP
• Farmall C series
• SR175
• SV250
• TR320

1. 1

   Check for related TVA circuit codes (such as 3818, 3819, or 3821–3824). If short circuit codes are present, prioritize wiring checks.

2. 2

   Inspect the wiring harness between the ECU (60-pin engine connector, pins A34 and A49) and the TVA for chafed insulation, melted wires, or corrosion that could cause a short circuit.

3. 3

   Remove the intake piping from the Throttle Valve Actuator and manually inspect the butterfly valve for mechanical binding or heavy carbon/soot buildup.

4. 4

   Disconnect the TVA and measure the electrical resistance across the actuator motor pins to check for an internal short in the actuator itself.

1. 1

   Disconnect battery

   Turn off the machine's ignition and disconnect the negative battery cable to protect the ECU.

2. 2

   Locate TVA

   Locate the Throttle Valve Actuator on the engine's intake manifold.

3. 3

   Disconnect harness

   Disconnect the electrical harness connector from the TVA.

4. 4

   Remove intake piping

   Loosen the retaining clamps and remove the intake air piping/hoses connected to the throttle body.

5. 5

   Remove mounting bolts

   Remove the mounting bolts securing the TVA to the intake manifold.

6. 6

   Remove TVA

   Remove the faulty Throttle Valve Actuator and discard the old gasket.

7. 7

   Clean mating surface

   Thoroughly clean the mating surface on the intake manifold, ensuring no old gasket material or carbon debris falls into the intake.

8. 8

   Install new TVA

   Install the new Throttle Valve Actuator using a new OEM gasket.

9. 9

   Tighten bolts

   Tighten the mounting bolts to the manufacturer's specified torque.

10. 10

    Reinstall intake piping

    Reinstall the intake air piping and securely tighten the clamps.

11. 11

    Reconnect harness

    Reconnect the electrical harness to the new TVA.

12. 12

    Reconnect battery

    Reconnect the negative battery cable.

13. 13

    Clear code and verify

    Connect the Electronic Service Tool (EST) to clear the inactive 3820 fault code, then run the engine to verify the repair and ensure the code does not return.