Case IH 3823 – Engine Control Unit (ECU): Throttle Valve Actuator (TVA) Circuit - Short Circuit To Ground

The Engine Control Unit has detected a 'Short circuit to ground on Out1 error for H-bridge'. The H-bridge is the internal circuitry used to drive the Throttle Valve Actuator motor, and the fault is specifically traced to Pin A49 on the 60-pin engine connector.

• skid steer
• Farmall 95U Pro EP
• Farmall 105U Pro EP
• Farmall 115U Pro EP
• SR175
• SSL/CTL models with F5C/F5H engine

1. 1

   Ensure the ignition key is in the OFF position before disconnecting any electrical connectors to prevent module damage

2. 2

   Disconnect the 60-pin engine connector (Connector A) at the ECU and the connector at the Throttle Valve Actuator (TVA)

3. 3

   Perform a continuity test to ground on the wire corresponding to Pin A49 of the 60-pin connector

4. 4

   If the wiring harness does not show a short to ground, check if the short circuit is internal to the Throttle Valve Actuator itself

1. 1

   Switch the ignition key to the OFF position.

2. 2

   Locate the Engine ECU and disconnect the 60-pin 'A' connector.

3. 3

   Locate the Throttle Valve Actuator (TVA) on the engine intake and disconnect its electrical harness.

4. 4

   Using a multimeter, test the circuit wire running from ECU Pin A49 to the TVA for a short to ground.

5. 5

   If the wire is shorted, trace the engine wiring harness to find where it is rubbing or chafing against the engine block or chassis.

   Repair the damaged wire or replace the engine wiring harness.

6. 6

   If the wire is good (no short to ground), remove the defective Throttle Valve Actuator and install a replacement unit.

   The H-bridge short is internal to the actuator.

7. 7

   Reconnect all harnesses, turn the ignition on, and use an electronic service tool (EST) to clear the fault code and verify the repair.