Epson L1800 Paper-Feed Errors: How to Diagnose PF Sensor Issues and Restore Proper Operation

Customer Question

I'm trying to determine whether the PF sensor in an Epson L1800 is failing. The printer stopped powering the fan and the white-ink circulation panel, and the INK light kept blinking. The waste pad was replaced and the counter was reset using the Adjustment Program, but the errors continue. The program keeps reporting waste-pad or paper-jam errors even though there's no jam. Printer Information shows paper-jam-related error codes, and when I opened the machine, the PF sensor looked discolored, almost like it overheated.

My questions are:
A) Does this sound like a PF sensor failure, and is the part available?
B) After replacing the sensor, does anything else need to be reset in the Adjustment Program?
C) For long-term care, are there other Adjustment Program features that should be used periodically besides resetting the waste-ink counter?
D) Any additional guidance for resolving the root cause of this issue?

Answer

Based on the symptoms and error codes you described-particularly E4H, F4H, and 05H-here is the detailed breakdown:

A) Is the PF Sensor the Likely Failure, and Is the Part Available?

We do carry the PF sensor, along with nearly all parts for the Epson L1800 and R1390. So availability is not an issue.

However, based on the error-code sequence you provided, the PF sensor is not necessarily the root cause. Your recent errors include:

• E4H - Paper Feed Overload
  Indicates PF motor overload, mechanical blockage, or encoder issues.

• F4H - PF PID Lock Error
  Points to PF encoder failure, PF motor malfunction, PF mechanism overload, FFC cable disconnection, PF motor-driver failure, or mainboard fault.

• 05H - CR PID Speed Fall Error
  Linked to CR encoder failure, CR motor driver issues, timing-belt tooth skipping, tension problems, or genuine paper jam.

Because these codes point repeatedly to motor load, encoder reading issues, or FFC/cable interruption, it is not certain that the PF sensor is the component that failed, even though it looks discolored. PF sensor discoloration is common after years of heat exposure and does not always indicate failure.

Before replacing the sensor, I recommend:

1. Running the printer several cycles
   See if the unit consistently returns F4H or E4H. Those recurring codes help pinpoint whether the feed system is locking mechanically or losing encoder detection.

2. Checking the PF motor connection
   A loose motor plug can generate this exact set of codes.

3. Inspecting the PF encoder wheel and encoder sensor
   Dust, ink mist, or a shifted encoder can cause false paper-jam readings.

4. Examining FFC cables
   A cable partially lifted from its socket can trigger both F4H and E4H.

So, while the PF sensor could be involved, it is often not the sole failure point for error combinations like this.

B) After Replacing the PF Sensor, Is Anything Else Required in the Adjustment Program?

If you do decide to replace the PF sensor, the Adjustment Program does not normally require an additional reset specifically for this component.

However, you should:

• Clear the protection counter if prompted

• Perform the PF/CR encoder tests to ensure proper detection

• Run the paper-feed calibration (PF adjustment) if the printer behaves inconsistently after the replacement

There is no dedicated "PF sensor reset," but the tech checks ensure that the new sensor communicates correctly with the mainboard.

C) Long-Term Maintenance: Any Other Adjustment Program Functions to Use?

The only Adjustment Program function that should be done periodically is the:

• Waste-ink counter reset

Other functions-such as CR/PF calibrations, EEPROM writes, and board initializations-should not be run unless troubleshooting requires them. Running unnecessary AP adjustments can cause more harm than good.

The best long-term maintenance steps are physical:

• Keep the encoder strip and encoder wheel clean

• Maintain correct belt tension

• Inspect FFC cables periodically

• Listen for unusual motor drag or friction

D) Additional Advice for Resolving the Original Issue

Since your L1800 is showing a repeating pattern of E4H → F4H → 05H, the printer is signaling:

• Mechanical overload or resistance

• Loss of encoder signal

• Possible PF motor under-load or driver failure

Here are the most effective steps to isolate the cause:

1. Check PF motor resistance by hand
   Gently rotate the PF gear. It should move smoothly with firm but even resistance.

2. Inspect the PF mechanism for clogs or drag
   Dried ink near the paper-feed roller area can create drag heavy enough to trigger E4H.

3. Verify all FFC cables are fully seated
   Even a 1 mm lift can cause communication loss.

4. Test the PF motor driver (on the mainboard)
   If the printer consistently shows F4H immediately upon startup, the driver may be failing.

5. Run the printer without paper to test whether the initial motor sweep completes without overload.

You're absolutely on the right track by examining the PF sensor, but I encourage checking these other components before committing to part replacement.

Addressing printer issues can be complex due to the hands-on mechanical nature of these systems. Because of this, we're not able to provide remote troubleshooting, suggestions, or repair support beyond general guidance. We do offer in-person diagnostic and repair services at our local facility through our Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Due to high demand, service is first-come, first-served, and wait times may be a few weeks. Our services cover full-printer repairs or individual-component repairs, with clear instructions on how to proceed. That said, our rates may not be the most affordable. For many users, the best approach is self-help using online resources-starting with YouTube or the search tool on our BCH Technologies YouTube homepage (https://youtube.com/@bchtechnologies). With nine years of videos, I receive dozens of requests daily for specific content, so using YouTube's search bar is truly the most efficient way to find what you need-including videos from other creators who may also help.

Thank you again for reaching out, and we sincerely appreciate your support of BCH Technologies. Your engagement helps us continue improving and creating more helpful content for the community.