New Holland 19075 – DCU / ECM: DEF Suction Tube Heater Short to Ground

Fault code 19075 indicates a short circuit to ground ('mass') in the electrical circuit supplying power to the tubular heaters (UB2) for the reagent (DEF) suction tube. These heaters warm the DEF to prevent freezing in cold conditions. A short circuit means electrical current is bypassing its normal path and flowing directly to the chassis, causing the control module to detect voltage below the expected range. If unresolved, this will illuminate the Malfunction Indicator Lamp (MIL), display a 'Service Emission System' message, and can lead to reduced engine power.

• T7.175
• T7.190
• T7.210
• T7.225
• T7.230
• T7.245
• T7.260
• T8.275
• T8.330
• T8.360
• T9.480
• T9.530
• T9.565

1. 1

   Confirm fault code 19075 (or equivalent J1939 code P20C3) is active using a diagnostic scanner and check for other related codes.

2. 2

   Visually inspect the wiring harness and connectors associated with the SCR suction tube heater for burnt or frayed wires, loose connections, or corrosion.

3. 3

   Check the power supply to the SCR control system using a multimeter, ensuring relevant fuses are tested under load to avoid misdiagnosis.

4. 4

   Perform a heater circuit voltage test: With ignition on (engine off), measure voltage between the power supply pin on the heater's harness connector and chassis ground. It should be greater than 11.5V. Insufficient voltage points to an upstream power supply or control module issue.

5. 5

   Perform a heater element resistance test: Disconnect the reductant pump/sensor assembly and measure resistance between the heater power supply pin and ground pin at the tank connector. A reading under 10 MΩ indicates an internally grounded/faulty heater.

1. 1

   Disconnect power

   Disconnect the vehicle's battery before starting any electrical repairs to prevent short circuits or injury.

2. 2

   Access the component

   Locate the DEF/reagent suction tube, which runs from the DEF tank to the dosing module. The heater is typically integrated into this line.

3. 3

   Repair wiring or replace heater tube

   If only the wiring is damaged, repair it using appropriate connectors and heat-shrink tubing. If the heater element is faulty (failed resistance test), replace the entire heated line assembly by disconnecting the electrical connector and fluid line fittings (prepare for residual DEF spills), then install the new assembly securely to prevent leaks.

4. 4

   Reconnect and clear codes

   Reconnect the battery and clear the fault codes using a diagnostic scanner.

5. 5

   Verify system operation

   Start the tractor and let it run for approximately 30 minutes to allow the system to perform a self-check. Reread the fault codes to ensure the code has not returned.