Epson Printer Still Flashing Blue and White Lights After Replacing the Printhead, Motherboard, Cables, 13-Pin Cable, and Sensor Cable

Question

I replaced several major parts in my Epson printer, including the printhead, motherboard, cables, 13-pin cable, and sensor cable, but the printer is still showing flashing blue and white lights. What else should I check, and how can I find out what error the printer is actually reporting?

Answer

When an Epson printer continues flashing blue and white lights after replacing the printhead, mainboard, and cables, the next step is not to replace more parts blindly. The flashing lights are only the printer's visible warning. To know what the printer is actually complaining about, you need to read the internal error code.

For Epson printers, especially models commonly converted for DTF or DTG use, the most useful tool is the Epson Adjustment Program. This is software normally used by Epson technicians, but some DTF printer sellers also provide it to customers. The Adjustment Program can show the printer's stored error history, which is much more helpful than trying to guess based only on the blinking lights.

Here is the basic process:

1. Open the Epson Adjustment Program for your specific printer model.

2. Select the correct USB port from the dropdown menu. Make sure you choose the USB port that shows your printer's name.

3. Click Particular Adjustment Mode.

4. Scroll down and select Printer Information Check.

5. Click Check.

6. Look at the error list. The most recent error is usually listed at the top as Error 1.

That top error code is the most important one. It tells you what the printer detected most recently, even if you have already replaced several parts.

Once you have the error code, you can search Google for "BCH Epson Error". That should lead you to our page explaining Epson's "Triple Secret Error Codes," which can help interpret the error number. These Epson error codes are often not shown clearly on the printer screen, which is why the Adjustment Program is so useful.

For example, if the Adjustment Program reports an APG-related error, then the issue may not be the printhead, motherboard, or 13-pin cable at all. APG usually refers to the automatic platen gap or carriage gap mechanism. In that case, the printer may be detecting a problem with the APG sensor, APG motor, gear position, carriage movement, or a related mechanical alignment issue.

Flashing blue and white lights can be caused by many different faults, including:

A printhead-related error, especially if the head is not seated properly, the head cable is damaged, or the printhead is shorted.

A carriage movement error, where the carriage cannot move freely or cannot find its expected position.

A CR encoder problem, such as a dirty encoder strip, damaged encoder sensor, or incorrect sensor cable connection.

A paper feed or PF encoder problem, especially if the printer cannot detect movement correctly in the feed mechanism.

An APG sensor or APG motor error, where the printer cannot confirm the correct platen gap position.

A cable connection problem, even if the cable is new. New cables can still be inserted crooked, reversed, not fully seated, or damaged during installation.

A mainboard mismatch or defective replacement board. If the board was taken from another printer or purchased used, it may have a different fault history or may not be fully compatible.

A sensor flag or mechanical lever being out of position. Sometimes the electronics are fine, but the printer is failing because a small plastic flag, gear, spring, or sensor arm is not where the printer expects it to be.

Since you already replaced the printhead, motherboard, cables, 13-pin cable, and sensor cable, I would not recommend replacing more parts until you retrieve the actual error code. Otherwise, you may keep replacing working parts while missing a mechanical or sensor-position issue.

Also, when replacing the motherboard and printhead, please be very careful with cable orientation. On many Epson models, the FFC cables can physically fit even when they are slightly misaligned or inserted at an angle. A printhead cable that is not seated evenly can cause immediate errors. A damaged or shorted printhead cable can also damage the board or printhead. Always power off and unplug the printer before removing or reconnecting any cable.

You can also check the carriage path manually with the printer powered off and unplugged. Make sure the carriage can move smoothly from side to side, the encoder strip is clean and seated correctly, and no ink tube, waste ink line, damper, cable, or DTF modification is blocking the carriage. If the printer was converted for DTF, also check that the ink lines are not pulling the carriage or creating tension during startup.

For a quick walkthrough of how to check the Epson error code using the Adjustment Program, you can watch our YouTube Short here: Epson Adjustment Program error check video [https://youtube.com/shorts/FPZzpyYuZLE].

The key point is this: the blue and white flashing lights tell us the printer has a serious error, but they do not tell us exactly which component is causing it. The Adjustment Program's Printer Information Check will give you the real error code. Once you have that code, you can narrow the problem down much more accurately.

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, repair suggestions, or printer repair support in a complete one-on-one way. 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]. Due to high demand, we operate on a first-come, first-served basis, so it may take a few weeks before we can schedule your printer for drop-off. Our services are structured to repair either the whole printer or specific parts, with clear instructions on how to proceed. We also understand that our rates may not be the most economical option, so we highly recommend self-help through online research. You can begin by checking YouTube or visiting our YouTube channel homepage: BCH Technologies on YouTube [https://youtube.com/@bchtechnologies]. Use the search icon next to "About" on the right-hand side of the channel menu bar to search for specific topics. I receive dozens of questions every day asking whether we have videos on particular issues. Since we have created videos for over nine years, it is difficult to remember every single one, so YouTube's search function is usually the most efficient way to find the right video. YouTube may also suggest helpful videos from other channels.

Thanks again for contacting us and for supporting BCH Technologies. I hope checking the stored Epson error code helps you move from guessing to a more exact diagnosis.