Case IH 19174 (DTC 467A) - ECU – Engine Control Unit (ECU): DEF/AdBlue dosing valve actuator short circuit in high side failure.

The control module has detected a short circuit to a high voltage source (short to battery/power) on the high side of the DEF/AdBlue dosing valve actuator circuit. Because of this short, the system cannot properly actuate the valve to inject Diesel Exhaust Fluid (DEF) into the exhaust stream. This will trigger an emissions system failure, illuminate the stop engine/warning light, and eventually force the engine into a derated state (power loss or forced low idle).

• MAXXUM T4E
• Axial-Flow Combines 240 Series (7240, 8240, 9240)
• Axial-Flow Combines 230 Series (7230, 8230, 9230)
• Magnum Tractors (180 to 380)
• Maxxum Tractors (115 to 150)
• Puma Tractors (140 to 240)
• Optum Tractors

1. 1

   Inspect the wiring harness running from the Engine ECU to the DEF dosing valve for chafed wires, melted insulation, or pinched areas.

2. 2

   Disconnect the DEF dosing valve connector and the ECU main connector to check the pins for corrosion, moisture intrusion, or bent terminals.

3. 3

   Test the high-side circuit wire between the ECU and the dosing valve with a multimeter for a short to voltage (with the key ON) and a short to ground.

4. 4

   Measure the internal resistance of the DEF dosing valve actuator pins to determine if the internal solenoid is shorted out.

1. 1

   Safely power down

   Turn off the machine, command the engine to low idle, shut it down, and disconnect the battery (negative pole first) to prevent damage to the ECU.

2. 2

   Locate the component

   Locate the DEF dosing valve (injector), which is mounted on the exhaust/SCR aftertreatment pipe.

3. 3

   Isolate the fault

   Disconnect the electrical connector to the dosing valve. If diagnostic testing (above) proved the wiring harness is shorted, repair or replace the damaged section of the harness.

4. 4

   Replace the valve (if internally shorted)

   Unbolt the DEF dosing valve from the exhaust system. Clean the mounting port on the exhaust pipe to ensure no crystallized DEF debris falls into the exhaust.

5. 5

   Install the new part

   Install the new DEF dosing valve using a new gasket/seal. Torque the mounting bolts to OEM specifications and reconnect the electrical harness.

6. 6

   Re-initialize the system

   Reconnect the battery. Connect a diagnostic tool (such as the CNH Electronic Service Tool) to clear the stored 19174 / 467A fault codes.

7. 7

   Verification

   Run an AdBlue/DEF dosing valve control test or force a stationary regeneration to verify that the dosing valve actuates properly and the system builds correct pressure without throwing the code.