New Holland DCU 19056 – DCU: UREA Temperature sensor in box (electrical) | signal low

The temperature sensor located inside the Diesel Exhaust Fluid (DEF/Urea) pump module is sending a voltage signal that is below the minimum acceptable threshold, typically caused by a short circuit low (short to ground) either within the sensor itself or in the wiring harness connecting the pump to the control module.

• T6 Series
• T6.160
• T7 Series
• T7.165
• T8 Series
• T8.320
• T8.380
• T9 Series
• T9.435
• T9.600
• CR Series
• CR6.80
• CR8.90
• CR10.90
• CX Series
• CX7.90
• FR Forage Harvesters
• FR480
• FR650
• Grape Harvesters
• 9050L
• SP370F
• Speedrower series
• LM series telehandlers

1. 1

   Inspect the wiring harness running from the DCU to the DEF pump module for chafed insulation, pinched wires, or areas shorting to the chassis.

2. 2

   Disconnect the main electrical connector at the DEF pump and inspect pins for corrosion, bent terminals, or moisture intrusion (DEF fluid wicking).

3. 3

   Use a multimeter to check the sensor signal wire and the 5V reference wire at the harness connector for a short to ground.

4. 4

   Connect an OEM diagnostic scan tool to view live data for the DEF pump temperature. An extreme default value (e.g., -40°C) that does not change indicates internal sensor failure if external wiring is good.

1. 1

   Prepare machine

   Turn off the machine, remove the key, and disconnect the battery to prevent accidental priming or electrical shorts.

2. 2

   Locate and clean pump

   Locate the DEF supply module mounted on a bracket near the DEF tank. Clean the exterior of the pump and surrounding fittings thoroughly to prevent dirt from contaminating the SCR system.

3. 3

   Disconnect lines and harness

   Disconnect the electrical harness connector. Carefully disconnect the DEF suction and pressure lines, as well as the engine coolant heating lines (if equipped). Have a catch pan ready, as coolant and DEF fluid will leak out.

4. 4

   Remove the pump

   Unbolt the pump module from its mounting bracket and remove the unit.

5. 5

   Install the new pump

   Mount the replacement DEF pump module and tighten the securing bolts.

6. 6

   Reconnect system

   Reconnect the DEF fluid lines, coolant lines, and the electrical harness connector. Ensure all fittings click into place securely.

7. 7

   System prime and reset

   Reconnect the battery. Use a diagnostic scan tool to prime the DEF system, perform a leak test, and clear the fault codes. Perform an 'Inducement Unlock / Counter Reset' via the diagnostic software to remove the emissions derate.