New Holland DCU 19182 – DCU: Reverting valve (4-2way valve?) electrically | Short circuit to ground | P20A2 Vent valve (Reductant Purge Control Valve) - short circuit low

The control module has detected a short circuit to ground (low voltage) on the electrical circuit that commands the reverting valve. Because the reverting valve is housed internally within the DEF pump assembly, this often points to an internal failure of the pump module itself if the external wiring is intact.

• T6
• T7
• T8
• T9
• TS6
• W130
• W190B
• Magnum
• Steiger
• Puma
• Maxxum

1. 1

   Turn OFF the ignition switch.

2. 2

   Inspect the wiring harness and the connector at the DeNOx supply module (DEF pump) for chafing, corrosion, or pinched wires that could be grounding out against the machine's chassis.

3. 3

   Disconnect the DeNOx supply module harness connector from the DCU. Test the power supply and ground circuits between the DCU and the pump module for an open circuit, high resistance, or a short to ground.

4. 4

   If the wiring harness tests perfectly fine with no shorts to ground, the short is internal to the reverting valve inside the DeNOx supply module.

1. 1

   Ensure the machine is off and the DEF system has depressurized.

2. 2

   Locate the DeNOx supply module (DEF pump) on the machine frame.

3. 3

   Open the locking lever and disconnect the main wiring harness connector from the DeNOx supply module.

4. 4

   Disconnect the DEF supply and return line hoses from the bottom of the module.

   Be prepared for minor fluid spillage; clean up any spilled DEF immediately with warm water to prevent corrosion.

5. 5

   Loosen and remove the mounting bolts securing the module's support bracket to the frame.

6. 6

   Remove the faulty DeNOx supply module.

7. 7

   Install the new module, reconnect the fluid lines and wiring harness, and clear the fault codes using a diagnostic tool.

8. 8

   Run a DEF system dosing/purge test via the diagnostic tool to verify the reverting valve operates correctly.