John Deere Fault Code
Free · no signup3216.2
Yellow CEL; Potential derate; DPF regens becoming frequent.
System
ECU
Symptom
Yellow CEL; Potential derate; DPF regens becoming frequent.
Diagnosis & fix steps
Inlet NOx Sensor Drifted High.
LOGIC: The sensor signal is "out of bounds" for the current engine load/exhaust flow.
ACTION: 1. Check exhaust for leaks upstream of the sensor.
2. Verify DEF dosing is occurring.
FIX: Replace the Inlet NOx Sensor.
Red Seal field insights
These sensors are "consumables." If the machine has over 4,000 hours, they are likely just tired. Always replace the sensor and the module (it comes as one unit).
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