Samsung ML-451 Series Service Manual page 202

4. Alignment and Troubleshooting
► Error Code
M2–2310
► Error message
Paper jam at the bottom of duplex path.
► Symptom
The paper has jammed in the duplex path.
► Troubleshooting method
1) Check if the duplex clutch works normally and its connector is connected properly.
2) Check if the Regi. actuator works normally.
3) Check if the Regi. roller pressure is normal.
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