Case IH 19471 – Engine Control Unit (ECU) / Engine Control Module (ECM): Short circuit to battery error at the High Side of Exhaust flap powerstage

The control module has detected that the voltage on the high-side control circuit for the exhaust flap actuator is shorted to battery voltage (B+). The exhaust flap is a critical emissions component used to restrict exhaust flow and increase exhaust gas back pressure. This places a load on the engine, forcing it to inject more fuel and elevate exhaust temperatures so the Diesel Oxidation Catalyst (DOC) and Selective Catalytic Reduction (SCR) systems can reach their optimal operating temperatures for NOx reduction.

• Tier 4b
• Optum series (250, 270, 300 CVX)
• Magnum series (e.g., 250 CVT)
• Quadtrac series (e.g., 620)
• Farmall A series (110A, 120A, 130A, 140A)
• Maxxum series (115, 125, 135, 145)
• Vestrum series

1. 1

   Inspect the wiring harness running between the ECU and the exhaust flap actuator for chafing, melted insulation, or areas where the wire might be shorting directly to a 12V power source or another wire.

2. 2

   Disconnect the exhaust flap actuator connector and inspect it for water ingress, corrosion, or bent pins, which can bridge connections and cause a short.

3. 3

   Measure the voltage and resistance on the high-side control wire at the actuator connector to determine if the short to battery is located within the machine's wiring harness or if it is an internal short inside the actuator itself.

4. 4

   Verify that the exhaust flap is not physically stuck or obstructed by soot/carbon buildup, as mechanical binding can sometimes cause actuator motor faults or over-temperature conditions.

1. 1

   Turn off the machine, ensure the exhaust system has cooled down, and disconnect the battery.

2. 2

   Locate the exhaust flap assembly.

   Typically mounted directly against the turbocharger outlet.

3. 3

   Disconnect the electrical harness connector from the exhaust flap actuator.

4. 4

   Repair the damaged section of the harness or replace it, or replace the exhaust flap assembly.

   If your diagnostics proved the wiring harness is shorted, repair the damaged section of the harness or replace it. If the actuator is internally shorted, proceed to replace the exhaust flap assembly.

5. 5

   Disconnect the exhaust pipe from the exhaust flap.

6. 6

   Disconnect the coolant supply and return lines from the actuator.

   Because the exhaust flap actuator is often cooled by engine coolant.

7. 7

   Remove the retaining bolts from the support bracket.

8. 8

   Loosen and remove the V-band clamp securing the exhaust flap assembly to the turbocharger, then remove the old unit.

9. 9

   Position the new exhaust flap assembly against the turbocharger and loosely install the clamp.

10. 10

    Install the support bracket bolts and torque them to 37 - 49 N·m (27.3 - 36.1 lb ft).

11. 11

    Tighten the turbocharger clamp securely.

12. 12

    Reconnect the coolant supply and return lines, the exhaust pipe, and the electrical connector.

13. 13

    Reconnect the battery, clear the fault codes using the Case IH Electronic Service Tool (EST), and run the engine to verify that the SCR system reaches operating temperature without triggering the code.