Epson Printer Error 100016 After Cable Replacement: Carriage Stops Midway and Won't Move Past a Certain Point

Question:
After replacing several internal cables and carefully reinstalling gears and the scanner assembly, my Epson printer powers on and the printhead moves from right to left, then back toward its home position. However, when it starts moving to the right again, it suddenly stops at the same spot every time and throws error code 100016. I've checked for debris, verified cable orientation using reference photos, ensured gears move freely in both directions, and even updated the software. Reassembling the scanner didn't help either. Is there something I may have missed or another area I should check?

Answer:

Regarding error code 100016, this is a critical clue. On many Epson inkjet models, this error typically points to a carriage movement or positioning failure. The fact that the printhead consistently stops at the exact same physical location strongly suggests that the issue is not random, but mechanical or sensor-related.

Here are the most common causes to investigate, especially considering the work you've already done:

1. Encoder Strip or Encoder Sensor Issues
   Even if the encoder strip (the clear plastic strip running horizontally behind the carriage) looks clean, a very small smudge, fingerprint, or slight misalignment can cause the printer to lose positional feedback. If the encoder sensor on the carriage can't properly read the strip at a certain point, the printer will immediately halt movement and throw error 100016.

   • Make sure the encoder strip is fully seated in its slots on both ends.

   • Clean it gently with lint-free cloth and isopropyl alcohol-no pressure.

   • Confirm the encoder sensor is not bent, cracked, or blocked by a cable.

2. Cable Routing and Carriage Harness Tension
   Even if the cables are installed correctly at the connectors, improper routing can cause binding. When the carriage reaches a certain position, the cable bundle may tighten, snag, or pull just enough to stop movement.

   • Compare cable routing to factory paths as closely as possible.

   • Look for tension, twisting, or cables catching on the frame when the carriage reaches the failure point.

   • Pay special attention to the flat flex cables (FFC); a slight fold or stiff bend can cause intermittent faults.

3. Scanner Assembly and Home Position Sensors
   Since this is an all-in-one unit, scanner-related components matter more than many people realize. The printer relies on multiple initialization checks during startup. If the scanner carriage, scanner lock, or scanner home sensor is even slightly out of alignment, it can interfere with overall initialization and trigger carriage errors.

   • Double-check that the scanner rail is seated evenly.

   • Ensure no scanner cables are pinched or pulling on the main harness.

   • Verify that any optical sensors related to scanner home position are unobstructed.

4. Carriage Path Obstruction or Frame Deformation
   Even if gears move freely by hand, the frame itself may have a subtle obstruction-such as a shifted plastic guide, misaligned metal rail, or screw that's slightly too tight.

   • Slowly slide the carriage by hand (with power off) past the problem area and feel for resistance.

   • Inspect the rail for scoring, bends, or debris that only interferes at that specific location.

5. Firmware vs. Hardware Reality
   While software updates are good practice, error 100016 is almost always hardware-triggered. Firmware simply reports what the sensors are detecting. Since the error persists after updates and reassembly, this further supports a mechanical or sensor feedback issue rather than a software one.

Addressing printer problems can be especially challenging because of their hands-on, mechanical nature. As a result, we're unable to provide remote troubleshooting, suggestions, or repair support beyond general guidance. That said, we do offer an in-person evaluation and repair service through our local diagnostic facility at Printer Repair Service by BCH Technologies (https://bchtechnologies.com/printer-repair-service). Due to high demand, all repairs are handled on a first-come, first-served basis, and there may be a wait of several weeks before drop-off availability. Our services are structured to repair either the entire printer or specific components, with clear instructions provided beforehand. While our rates may not be the most budget-friendly, we always aim for thorough and professional results.

For many users, we strongly recommend self-help through online research. A great starting point is YouTube, especially our BCH Technologies YouTube channel (https://youtube.com/@bchtechnologies). You can use the search icon near the "About" section on the right side of the channel page to look for specific topics. I receive dozens of messages daily asking whether I've made a video on a particular issue, and after more than nine years of creating content, it's difficult to recall every single one. Using YouTube's built-in search is the fastest way to find relevant videos, and it may also surface helpful content from other creators.

Thank you again for taking the time to reach out and for your patience. We truly appreciate your support and wish you the best of luck as you continue troubleshooting your printer.