What does an open circuit in the urea nozzle mean?
2 Answers
The urea nozzle, also known as the dosing module, is a stainless steel injector installed on the exhaust pipe. Purpose of the urea nozzle: Under the control of ODB, it sprays AdBlue in the required amount in a mist form, mixing the urea delivered by the metering injection pump with air. This ensures the sprayed urea solution is uniformly atomized before being injected into the exhaust pipe. When not spraying AdBlue (urea), the nozzle only sprays air to prevent it from being burned out. Material of the urea nozzle: The nozzle is made of stainless steel 304, processed by CNC machining and vacuum brazing. It operates in temperatures ranging from -40°C to 80°C. Function of the urea nozzle: It quantitatively sprays the exhaust after-treatment urea solution (AdBlue) to reduce NOx emissions. It is a wearable part and can be matched with Cummins, Renault, Yuchai, Weichai, and Xichai.
An open circuit in the urea nozzle means the circuit at the urea injection point is broken, preventing current flow and rendering it inoperable. I recently dealt with a similar issue in my own car when the fault light came on and the code indicated an open circuit. Possible causes include aged wiring, loose connectors, or moisture corroding the terminals, leading to the nozzle's failure to spray urea solution. This is problematic—SCR system failure results in excessive emissions, triggering a vehicle speed limitation mode that can be dangerous, as I nearly experienced on the highway. I had to enlist a knowledgeable friend to use a multimeter to test circuit continuity, locate and repair the break, and replace some oxidized components. Preventive measures include parking in dry areas, inspecting wire harness protection during maintenance, and addressing issues before warning lights appear. Checking urea tank levels is also crucial, as an empty tank can falsely indicate an open circuit. In short, timely resolution is key to safety.
