Case IH 19704 – Engine Control Module (ECM) or Dosing Control Unit (DCU): Diagnostic Fault Check for Supply Module Heater Temperature Duty cycle in invalid range

The control module has detected that the Pulse Width Modulation (PWM) duty cycle signal for the Diesel Exhaust Fluid (DEF) / AdBlue supply module heater is operating outside of its expected or valid parameters, indicating an electrical failure, an open/short circuit, or a failed temperature sensor.

• Tier 4b
• Magnum (180-370)
• Steiger/Quadtrac (350-600)
• Puma (130-240)
• Maxxum (110-150)
• Farmall series
• Axial-Flow series (5130, 6130, 7130, 7230, 8230, 9230)
• Patriot series
• Titan series
• Farmlift Telehandlers
• Motor Graders
• Crawler Dozers

1. 1

   Inspect the DEF supply module and its electrical connectors for corrosion, chafing, or crystallized white urea buildup which can cause electrical shorts.

2. 2

   Inspect the control circuit between the ECM/DCU and the DEF supply module using a multimeter to check for high resistance (open circuit) or low resistance (short circuit) on the heater circuit pins.

3. 3

   Verify that the ECM is sending the correct PWM signal to the supply module.

4. 4

   Connect the Case IH Electronic Service Tool (EST) to monitor the DEF supply module temperature sensor live data and perform a Urea Dosing Leak Check (UDLC) or a manual heater override test to see if the heater draws the correct amperage.

1. 1

   Preparation

   Turn off the ignition switch and disconnect the battery to prevent electrical spikes.

2. 2

   Clean the Area

   Thoroughly clean the exterior of the DEF supply module and surrounding tank area using only clean distilled water to flush the external housing to prevent contaminating the high-pressure fluid loops.

3. 3

   Disconnect Lines

   Disconnect the electrical harness from the module. Carefully disconnect the DEF suction, backflow, and dosing lines. Have a clean catch pan ready for spilled DEF.

4. 4

   Remove the Module

   Remove the mounting bolts securing the DEF supply module to its bracket or the DEF tank flange, and carefully extract the unit.

5. 5

   Filter Replacement

   If servicing, use the specialized extraction tool to remove the main DEF pump filter element from the reservoir without scratching the inner walls. Install a new filter and pre-filter strainer.

6. 6

   Installation

   Mount the new DEF supply module and torque the bolts to OEM spec. Reconnect the fluid lines (ensuring they click securely) and the electrical harness.

7. 7

   System Prime & Clear Codes

   Reconnect the battery. Turn the ignition ON without starting the engine. Use the Case IH EST to clear fault code 19704. Run a system prime test (UDLC) to pressurize the system to ~9000 mbar and verify there are no leaks.