Epson Error 0335xx and Print Alignment Problems After Replacing the Carriage and Timing Belt

Question

I watched your video about Epson Error 0335xx and replacing the PIS sensor on Epson WorkForce and Expression XP printers, including models like the XP-4105 and WF-2850. I need help with a print alignment problem. My printer has already had the carriage and timing belt replaced, but it still cannot print straight lines. What could be causing this, and how can I fix it?

Answer

For Epson printers such as the XP-4105, WF-2850, and similar WorkForce or Expression models, an error in the 0335xx range is often related to the printer's carriage positioning system. In many cases, this can involve the PIS sensor, the carriage movement, the timing belt, the encoder system, or the way the printer detects the carriage's position during startup and printing.

Since you already replaced the carriage and the timing belt, but the printer still cannot print straight lines, the issue may not be only the belt itself. Straight-line printing depends on several parts working together very precisely.

The first thing to check is the encoder strip. This is the clear plastic strip that runs behind the carriage. It has very fine markings that the printer uses to know the carriage's exact horizontal position. If the encoder strip is dirty, scratched, installed incorrectly, twisted, or sitting outside the sensor slot, the printer may still move the carriage, but it will not know the exact position correctly. That can cause crooked vertical lines, stair-step printing, misalignment, or text that looks shifted from one pass to the next.

Clean the encoder strip gently with a lint-free cloth and a small amount of distilled water or mild cleaning solution. Do not use strong solvents, because they can damage the fine markings on the strip. Also make sure the strip passes cleanly through the carriage sensor. If the strip is in front of or behind the sensor instead of inside the sensor gap, the printer may behave as if the carriage position is unstable.

Next, check whether the timing belt tension is correct. A belt that is too loose can cause the carriage to lag slightly during movement, which may result in crooked lines or poor bidirectional alignment. A belt that is too tight can create extra load on the carriage motor and may also cause movement problems. The belt should be seated properly on the motor pulley and the opposite pulley. It should not be riding on the edge of the pulley, skipping teeth, rubbing the frame, or installed with a twist.

Also inspect the carriage rail and the carriage movement. After replacing the carriage, the carriage should slide smoothly from left to right with no catching, grinding, or uneven resistance. If the carriage rail is dry, dirty, bent, or contaminated with ink residue, the carriage may not travel consistently. Even a small amount of mechanical resistance can affect print alignment. Clean the rail and apply only a very small amount of suitable lubricant if needed. Too much grease can attract dust and make the problem worse.

Another important area is the PIS sensor, especially since your question refers to Epson Error 0335xx and PIS sensor replacement. The PIS sensor helps the printer detect positioning or internal movement conditions, depending on the model design. If the sensor is dirty, unplugged, not seated correctly, or if the cable is damaged, the printer may still initialize but have positioning errors. Check the sensor cable carefully. Make sure the FFC cable is fully inserted, facing the correct direction, and locked into the connector. A slightly loose cable can cause intermittent problems that are very hard to diagnose.

Since the carriage was replaced, also confirm that the replacement carriage is exactly compatible with your printer model. Epson printers often look similar across the XP and WF series, but small differences in carriage design, sensor location, cable layout, or board compatibility can cause alignment and movement problems. A carriage that physically fits is not always electronically or mechanically identical.

If the printer can complete startup and print, then run the printer's built-in Print Head Alignment from the Epson maintenance menu or computer utility. This is especially important after replacing the carriage, belt, printhead, or any carriage-related component. However, if the printed alignment pattern is severely slanted or broken, then the problem is probably mechanical or sensor-related, not just a software alignment issue.

For crooked straight lines, also test both bidirectional and unidirectional printing if your driver allows it. In bidirectional printing, the printer prints while the carriage moves in both directions. If the timing is slightly off, vertical lines can look misaligned. Unidirectional printing is slower but can help confirm whether the issue is caused by bidirectional alignment. If lines look much better in unidirectional mode, then the carriage timing, encoder reading, or bidirectional calibration may still be off.

You should also inspect the printhead seating. If the carriage was replaced and the printhead was transferred, make sure the printhead is sitting flat and fully secured. A printhead that is slightly tilted can cause lines to print at an angle or create inconsistent alignment. Also check that the printhead cable is not pulling on the carriage or interfering with movement.

If the printer shows or previously showed Epson Error 0335xx, and now the main symptom is poor alignment, I would focus on these areas in this order:

1. Encoder strip cleanliness and correct routing through the carriage sensor.

2. Timing belt installation, tooth engagement, and tension.

3. Smooth carriage movement along the rail.

4. PIS sensor seating, cable direction, and connector condition.

5. Correct compatibility of the replacement carriage.

6. Printhead seating and cable routing.

7. Built-in Epson alignment calibration after the mechanical checks are complete.

One common mistake after replacing the carriage or belt is assuming that the problem is solved once the printer moves again. In reality, Epson printers need extremely accurate carriage position feedback. The printer may move normally but still print crooked lines if the encoder strip or sensor cannot read the carriage position precisely. That is why I would not replace more parts immediately until you carefully inspect the encoder strip, sensor path, and belt alignment.

Addressing printer issues can be a complicated affair because many of these problems require hands-on inspection. For that reason, we are not able to provide remote troubleshooting, detailed repair guidance, or direct repair support for individual printers. However, we do offer an in-person evaluation and repair service through our local diagnostic facility: BCH Technologies Printer Repair Service [https://bchtechnologies.com/printer-repair-service]. Because demand is high, we operate on a first-come, first-served basis, so it may take a few weeks before you can bring or ship your printer in for service. Our repair service is structured to work on either the whole printer or specific printer parts, with clear instructions on how to proceed. We also understand that our rates may not be the most economical option for everyone, so we highly recommend self-help through online research. A good starting point is YouTube, including our homepage at BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Once you are on the channel page, use the search icon next to "About" on the right-hand side of the menu bar to look for videos related to your specific printer model, error code, encoder strip, carriage, timing belt, or alignment issue. I receive many questions every day asking where to find videos on specific topics, and after making repair videos for more than nine years, it is difficult to remember every exact video. YouTube's search function is usually the fastest way to find the most relevant tutorial, and it may also suggest helpful videos from other repair channels.

Thank you again for your question and for supporting BCH Technologies. I hope this gives you a clearer direction for checking the printer after replacing the carriage and timing belt.