Case IH 19838 – Engine Control Module (ECM / ECU): SCG error on the Turbocharger PWM output powerstage

The engine's control system uses a Pulse Width Modulation (PWM) signal to precisely control the turbocharger's wastegate actuator or boost pressure control solenoid. This fault code indicates that the control module has detected a short circuit to ground (SCG) on the electrical circuit (the 'output powerstage') that drives this turbocharger actuator.

• Tier 4b
• Magnum
• Steiger
• Puma
• Maxxum
• Farmall Pro series
• Farmall 100A Pro
• Farmall 120A Pro
• Farmall 150A Pro
• N-Series Tractor Loader Backhoes
• 580N
• 590SN
• heavy-duty wheel loaders
• T6
• T7
• T6000 series
• T7000 series

1. 1

   Visually inspect the engine wiring harness routing from the Engine ECU to the turbocharger wastegate actuator/solenoid for chafed insulation, melted wires, or pinch points touching the engine block or chassis.

2. 2

   Perform an Actuator Disconnect Test: Disconnect the electrical connector at the turbocharger PWM control valve/actuator, cycle the key, and see if the code changes to an Open Circuit (code 19835) to determine if the short is internal to the actuator.

3. 3

   Perform a Harness Continuity Test: With the battery disconnected and both the ECU and actuator unplugged, use a multimeter to check for continuity between the PWM signal wire and a known good chassis ground.

4. 4

   Inspect the ECU connector pins for water intrusion, bent pins, or corrosion that could bridge the PWM output pin to a ground pin.

1. 1

   Power Down

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

2. 2

   Access the Turbocharger

   Locate the turbocharger assembly and its attached electro-pneumatic boost control solenoid or electronic wastegate actuator.

3. 3

   Address Wiring (If Applicable)

   If the diagnostic tests revealed a harness short, carefully open the wire loom, locate the bare wire shorting to the block, repair it with heat-shrink solder connectors, and re-loom the harness away from high-heat areas.

4. 4

   Replace the Actuator (If Applicable)

   If the actuator is internally shorted: Disconnect the electrical connector. Remove the vacuum/pneumatic lines (if it is an electro-pneumatic valve) or unbolt the mechanical linkage (if it is a direct electronic actuator). Unbolt the actuator bracket and remove the faulty unit. Install the new OEM actuator, reconnect the linkage/hoses, and plug in the electrical connector.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery. Connect the CNH Electronic Service Tool (EST) or a compatible diagnostic scanner to clear the inactive 19838 fault code.

6. 6

   Test Run

   Start the engine and run it under load to verify that turbocharger boost pressure is regulating correctly and the fault code does not return.