Case IH 19478 – Engine Control Module (ECM / ECU): Over Temperature error at the Low Side of Exhaust flap powerstage

The exhaust flap actuator is overheating, which is usually caused by a supply problem, a wiring short on the low side of the circuit, or increased mechanical resistance (friction) forcing the actuator motor to work too hard.

• Tier 4b
• Steiger
• Magnum
• Maxxum
• Axial-Flow

1. 1

   Check the physical exhaust flap in the exhaust duct for mechanical binding or carbon buildup

2. 2

   Inspect the exhaust flap actuator supply voltage

3. 3

   Inspect the wiring harness (specifically the low-side connection wire to the exhaust flap) for a short circuit to ground or a short to the battery

4. 4

   Test the actuator motor itself for internal shorts or abnormally high electrical resistance

1. 1

   Safety First

   Turn off the vehicle and allow the exhaust system and aftertreatment components to completely cool down to avoid burns and to ensure accurate sensor/resistance readings.

2. 2

   Isolate the Flap

   Disconnect the linkage between the exhaust flap actuator and the exhaust flap. Move the flap by hand to verify if it moves freely. If it binds, clean the exhaust flap housing of soot/carbon or replace the mechanical flap assembly.

3. 3

   Harness Repair

   Disconnect the actuator and test the harness pins back to the ECM. If a short to ground is found on the low-side control wire, repair or replace the damaged section of the wiring harness.

4. 4

   Replace Actuator

   If the wiring is intact and the mechanical flap moves freely, the actuator's internal powerstage is damaged. Replace the Exhaust Flap Actuator.

5. 5

   Clear Codes

   Reconnect all components, turn the ignition key ON, and use the Case IH Electronic Service Tool (EST) to clear the fault codes and perform an auto-calibration of the exhaust flap if required.