How to Fix a Persistent "Fake Carriage Jam" Error: Detailed Q&A for Printer Owners

Question

A customer reports that their printer repeatedly shows a "carriage jam" error-specifically what appears to be a fake carriage jam. Even after installing a new printhead and cartridges, the printer still displays the same message, and the printhead carriage slams left and right violently. They purchased and installed a new 15-pin carriage cable, which allowed the printhead to glide smoothly again, but the carriage jam error persists. They are considering replacing the encoder scale strip and ask whether this is the right next step or if there are other suggestions.

Answer

Understanding the "Fake Carriage Jam" Error

The carriage jam or "fake carriage jam" issue is among the more frustrating problems users encounter. The printer reports a jam-even when nothing is physically blocking the carriage-and symptoms often include:

• Carriage slamming rapidly left and right

• Carriage stopping abruptly

• Printer refusing to initialize

• Repeating "Carriage Jam", "Carriage Cannot Move", or similar error codes

These symptoms typically point to sensor-related failures rather than an actual obstruction.

What Typically Causes These Errors?

1. Carriage Cable Failure (15-Pin Cable)

You already replaced the 15-pin cable-which was a good first step.
A damaged, shorted, or partially broken cable can:

• Interrupt signals to the carriage motor

• Prevent the printer from reading positional data

• Cause erratic carriage movement

• Trigger false jam errors

The fact that your carriage now glides smoothly confirms that the cable replacement was successful.

2. Encoder Strip Issues

The encoder strip is the clear plastic band-printed with fine black markings-that runs the length of the carriage path. It tells the printer where the carriage is at any moment. If the strip is:

• Dirty

• Scratched

• Bent

• Loosely mounted

• Installed slightly off-center

• Missing lubricating coating

...the printer cannot accurately read carriage position.
This is one of the most common causes of a fake carriage jam.

Since your carriage behaves violently (slamming left/right), this strongly points to encoder signal loss. When the printer can't read the encoder strip, it continues "searching" for home position-often resulting in aggressive movement before throwing a jam error.

So yes-replacing the encoder strip is a logical next step, especially since other components have been addressed.

3. Encoder Sensor (Carriage Optical Sensor) Problems

Even with a new strip, the optical sensor on the carriage must be clean and functioning. Issues include:

• Ink splatter on the sensor

• Dust or paper fibers blocking the optical eye

• A cracked or loose housing

• Cable misalignment at the sensor end

If the sensor cannot "read" the encoder strip, the error persists.

Cleaning tip:
Use a lint-free swab lightly moistened with alcohol and gently clean:

• The encoder strip

• The slot of the optical sensor

Avoid pressure-these parts are delicate.

4. Mechanical Obstructions or Friction

Even if it appears to slide freely by hand, minor obstructions or friction points can still create false jams:

• Debris in the carriage path

• Loose belt tension

• Damaged printhead bushings

• Sticky lubricant buildup on the rail

• Dry or worn carriage bearings

Because the 15-pin cable now allows smooth movement, mechanical causes are less likely-but still worth inspecting.

5. Logic Board or Motor Driver Problems

Rare but possible:

• Motor driver failure

• Timing signal issues

• Corrupted initialization logic

• Static damage during cable installation

These deeper electrical failures produce similar symptoms but are usually the last concern after all mechanical and sensor-related causes have been eliminated.

Next Recommended Steps

Based on your description:

1. Replace the encoder strip - this is very likely the missing piece.

2. Clean the encoder sensor thoroughly.

3. Verify strip installation:

   • Centered in the optical sensor's slot

   • Tensioned evenly

   • No twists or sagging

4. Inspect the encoder sensor cable for kinks or loose seating.

5. Check carriage movement again and watch whether the printer correctly slows and homes instead of slamming.

If the strip or sensor was the culprit, the printer should resume normal, smooth initialization immediately after repair.

A Few Important Notes

Addressing printer issues can be complicated and very hands-on. Because of this, we're unable to provide remote repair, disassembly guidance, or step-by-step troubleshooting. However, we do offer in-person diagnostics through our Printer Repair Service at BCH Technologies (https://bchtechnologies.com/printer-repair-service). Due to high demand, repairs are processed on a first-come, first-served basis, and wait times can extend a few weeks. We repair either full units or specific components, and our service structure is very transparent. That said, our rates may not be the most affordable option, so we strongly encourage self-help through online research when possible.

A great place to start is our YouTube channel home page (https://youtube.com/@bchtechnologies)-use the search icon next to "About" to locate videos specific to your model or symptom. After nine years of creating technical videos, it's difficult to recall each one, and using YouTube search is the fastest way to locate exactly what you need. YouTube may also recommend videos from other channels that could help.

Thank you again for your patience and for supporting BCH Technologies. We truly appreciate your trust and engagement, and we hope this guidance helps you get your printer back to working condition soon. If you have more questions, feel free to reach out anytime.