Error Code 007-371

Error code 007-371 on your Dell 3130cn printer indicates an IOT K Mode Solenoid error, likely related to an internal motor issue. Try a power cycle, clearing print queues, and if the error persists, consider running a diagnostic test on the main motor in "Customer Mode". 
Here's a more detailed breakdown of troubleshooting steps:
1. Power Cycle and Clear Print Queue:
Power off: Turn off the printer and unplug all cables (USB or Ethernet).
Wait: Allow the printer to sit unplugged for a few minutes.
Clear Print Queue: Clear any pending print jobs from the printer's control panel or computer's print queue.
Power on: Plug in the cables and power on the printer.
Check for Error: Determine if the error recurs. 
2. Visual Inspection (If Error Persists):
Open Front Cover: With the printer powered on, open the front cover.
Inspect Belt Unit: Visually inspect the belt unit (also known as the transfer belt) for any scratches or damage.
Repeat Inspection: Open and close the front cover three times to inspect the entire surface of the belt unit. 
3. Further Troubleshooting (If Error Persists):
Run Diagnostic Test: If the error persists, try running a diagnostic test on the main motor in "Customer Mode". 
Check for Paper Jams: Ensure there are no paper jams in the printer's paper path or output tray. 
Update Firmware: Check for and install the latest firmware for your printer. 
Reinstall Driver: Try reinstalling the printer driver on your computer. 
Reset NVRAM: Reset the printer's NVRAM (Non-Volatile Random Access Memory) to factory defaults. 
Check for Corrupt Jobs: If the error persists, try printing a test page or a simple document to see if the error is related to a specific job. 

That error 007-371 usually points to a toner density sensor issue, often with the cyan cartridge. Try removing and reseating the cyan toner, or swap it if you have a spare. Sometimes just cleaning the sensor area helps too.