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.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

Book an uptime review

Read before you touch anything

  • This is general reference information, not a repair manual. It is for trained, qualified technicians.
  • Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
  • Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
  • You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
  • Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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