Deutz Fault Code
Free · no signupSPN 523470 FMI 2
Low power; Engine in limp mode; Rail pressure erratic.
System
Not specified
Symptom
Low power; Engine in limp mode; Rail pressure erratic.
Diagnosis & fix steps
Pressure Relief Valve (PRV) Fault
LOGIC: The PRV has "tripped" too many times or is leaking internally.
ACTION: Check the "PRV Opening Count" in the ECM. Check for fuel returning from the PRV line at idle.
FIX: Replace the Fuel Pressure Relief Valve and reset the PRV counter in the software.
Red Seal field insights
You cannot just replace the valve; you must reset the software counter, or the engine will stay in a "protection derate."
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