Case IH DCU19091 – DCU: Dosing Valve Supply Voltage Low

The Dosing Control Unit (DCU) has detected a low voltage condition in the power supply circuit (VDD11) for the DEF dosing module and dosing valve. The 12-volt power supply has dropped below the required minimum threshold, preventing the DEF dosing system from operating correctly. This condition can lead to increased emissions and eventual engine power derating.

• Puma 130
• Puma 145
• Puma 160
• Puma 170
• Puma 185
• Puma 200
• Puma 215
• Puma 230
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 315
• Magnum 340
• Magnum 370
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 135
• Maxxum 140
• Maxxum 145
• Maxxum 150
• Farmall 100C
• Farmall 110C
• Farmall 120C
• 5130 Combine
• 6130 Combine
• 7130 Combine
• 7230 Combine
• Patriot 4430 Sprayer
• Titan 3030 Floater
• Titan 3530 Floater
• Titan 4030 Floater
• Titan 4530 Floater
• 1150M Dozer
• 1650M Dozer
• 2050M Dozer
• 521F Wheel Loader
• 621F Wheel Loader
• 1021F Wheel Loader
• 1121F Wheel Loader
• FARMLIFT Telehandlers

1. 1

   Check for other fault codes using a diagnostic scanner to rule out systemic electrical issues

2. 2

   Inspect battery and charging system with a load tester and verify alternator output is 13.8 to 14.4 volts

3. 3

   Inspect the wiring harness and connectors leading to the DEF dosing module/pump and dosing valve for corrosion, damage, loose connections, or moisture

4. 4

   Verify proper 12V power and a clean ground connection directly at the Dosing Control Unit (DCU) electrical connector

5. 5

   Check fuses and relays associated with the after-treatment system and the DCU

1. 1

   Disconnect the Battery

   Before working on electrical components, disconnect the battery to prevent short circuits.

2. 2

   Locate the Dosing Module/Pump

   The dosing module (which often incorporates the pump) is a central component of the DEF system. Its location varies by machine but is typically mounted on the chassis near the DEF tank.

3. 3

   Test Voltage at the Dosing Module Connector

   Disconnect the electrical harness from the dosing module. With the key on, use a multimeter to test for 12V+ at the appropriate pin on the harness side of the connector. Refer to the machine's specific wiring diagram to identify the correct power supply pin.

4. 4

   Test for Short Circuits

   If voltage is low, unplug actuators that share the circuit one by one to see if the voltage recovers, indicating a short circuit in a downstream component.

5. 5

   Inspect the Dosing Valve

   Inspect the dosing valve connector on the exhaust system. Perform a resistance test on the valve; it should measure between 11 and 18 ohms. Replace if open or shorted.

6. 6

   Component Replacement

   If wiring, connectors, and power supply are good, replace the dosing module/pump assembly. Disconnect DEF lines and electrical connectors, unbolt the module, install the new one with correct gaskets, and reconnect.

7. 7

   Clear Codes and Verify Repair

   Reconnect the battery, clear DCU19091 and related codes with a diagnostic tool, and run the machine. A system test or regeneration cycle may be necessary to fully verify the repair.