Liebherr Fault Code

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P1122-00

Dosing Failure. AdBlue/DEF is not being sprayed into the exhaust.

System

Aftertreatment (SCR)

Symptom

Dosing Failure. AdBlue/DEF is not being sprayed into the exhaust.

Diagnosis & fix steps

SCR System (DEF Injector) - AdBlue Injection Path Blocked. LOGIC: The pump builds pressure, but the pressure doesn't "drop" when the injector is commanded to open. The ECU concludes the line or nozzle is plugged.

Red Seal field insights

Pro-Tip: In the high-dust environment of a drilling rig, the DEF injector nozzle tip is prone to "Urea Stalactites." Fix: Remove the injector (carefully, the plastic clips are brittle) and soak the tip in warm distilled water. Do not poke the tiny holes with a wire, as you'll ruin the spray pattern.

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