Case IH 19835 – ECM or VCM: Open load temperature error on the Turbocharger PWM output powerstage

The control module has detected an "open load" (an open electrical circuit or infinite resistance) on the Pulse Width Modulation (PWM) output circuit that drives the turbocharger's electronic wastegate or Variable Geometry Turbocharger (VGT) actuator. When this circuit is open, the engine cannot control the turbocharger vanes or wastegate, typically resulting in a derated engine state (limp mode) and low boost pressure.

• Tier 4b
• 580N
• 580SN
• 590SN
• 580SN WT

1. 1

   Inspect the wiring harness running from the ECM to the turbocharger actuator. Look for chafed wires, melted insulation from exhaust heat, or broken wires.

2. 2

   Disconnect the turbo actuator plug. Check for pushed-out pins, water intrusion, or heavy corrosion.

3. 3

   Using a multimeter, measure the resistance across the motor/coil terminals on the turbo actuator itself. If the reading shows an open circuit (infinite ohms/OL), the actuator has failed internally.

4. 4

   Check the continuity of the PWM signal wire and the ground wire from the actuator connector back to the ECM pins. If the wiring is intact but the code persists, the actuator is the culprit.

5. 5

   Ensure the sector gear or linkage arm on the turbocharger moves freely. If the turbo vanes are jammed with soot, it can burn out the electronic actuator.

1. 1

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

2. 2

   Locate the turbocharger on the exhaust side of the engine and disconnect the electrical harness from the electronic actuator.

3. 3

   If the wiring harness failed the continuity test, repair the broken wires or replace the damaged harness section.

4. 4

   If the actuator failed the resistance test, remove the mounting bolts securing the actuator to the turbocharger bearing housing/bracket.

5. 5

   Install the new turbocharger actuator.

   Note: Depending on the specific FPT/Holset turbocharger model, a new electronic actuator may require calibration to the turbocharger using the Case Electronic Service Tool (EST) software so the ECM learns the new end-stops.

6. 6

   If the actuator is not available as a separate serviceable part for your specific turbo model, the entire turbocharger assembly must be replaced.

7. 7

   Reconnect the battery, clear the fault codes using a diagnostic scan tool, and perform a test run under load to verify proper boost pressure.