Bambu Lab P1S Troubleshooting: 9 Common Issues Fixed

The Bambu Lab P1S is a great printer out of the box, but its enclosed design and firmware choices come with some unique headaches. Here are 9 P1S-specific issues you're likely to run into, with step-by-step fixes ranked from easiest to most involved. There's also an HMS error code table at the end. If you own a Bambu Lab A1 instead, check out our A1 troubleshooting guide.

Heat Creep: PLA Clogs in the Enclosed Chamber

The P1S enclosed chamber heats up to 40-50°C, and PLA has the lowest glass transition temperature (~60°C). Heat travels up past the heatbreak and softens the filament in the cold zone — the hotend fan simply can't keep up.

1. PLA: always print with the door open and/or the top glass removed
2. Bed temp: 55°C for Textured PEI (don't go higher)
3. Set the chamber fan to minimum when printing PLA
4. If already clogged: do a cold pull, then try the Hot Wrench Method
   1. Heat a 1.5mm hex key with a lighter for 10-15 seconds
   2. Insert through the heatsink, wait 30 seconds
   3. Heat the nozzle with a lighter for 20 seconds, then pull out
5. For ABS/ASA: enclosed chamber is fine, heat creep isn't an issue

Firmware and Authorization Control Lockdown

Bambu Lab introduced mandatory cloud authorization in firmware 01.09+. This blocks third-party software like OrcaSlicer and SimplyPrint, and it activates automatically when you update.

1. Don't update past firmware 01.08.00.00 if you use OrcaSlicer
2. Firmware 01.08 supports AMS 2 Pro without Authorization Control
3. Developer Mode preserves LAN printing, but with limitations
4. Update via microSD if the WiFi update fails
5. Warning: the update is irreversible — you can't roll back

AMS 2 Pro Compatibility Issues with P1S

The AMS 2 Pro ships with a 6-pin cable that doesn't plug into the P1S directly — you need a Filament Buffer or AMS Hub from the upgrade kit. Drying also requires a separate power adapter, and the P1S firmware must be 01.08 or higher.

1. Get the P1S upgrade kit (Filament Buffer + cables)
2. Update P1S firmware to 01.08.00.00+ (use microSD if needed)
3. For drying: buy the separate Bambu Lab power adapter
4. Check all cable connections — both 4-pin and 6-pin should click in
5. Don't route cables around sharp corners — internal wires break

Purge Chute Clogs During Multicolor Prints

During multicolor printing, filament waste sticks to the chute walls, and the wiper paddle gets jammed by built-up debris. This is a well-known P1S design issue.

1. Line the inside of the chute with aluminum tape — this is a 100% fix for the sticking issue
2. To clean: remove the back panel, unscrew 2x H1.5 screws, clear the chute
3. Update firmware (the November 2023 repair firmware improved wiper behavior)
4. Install a poop chute mod (MakerWorld) for external waste collection
5. Regularly clean the wiper brush to prevent filament buildup

Rattling Panels and Top Glass at High Speeds

The P1S side panels are only secured at the edges — the center is free to vibrate. The top glass just sits on top with no retention. If you press the middle of a panel with your hand and the noise drops significantly, that confirms the issue.

1. Check and tighten all panel mounting screws
2. Print clips to secure the center of the side panels
3. Top glass riser mod — raises the glass and improves ventilation
4. Anti-vibration feet (official or Floating Damper Feet)
5. Cable chain clip to hold the top glass in place

Carbon Filter Doesn't Handle the Smell

The stock P1S carbon filter is small and saturates quickly. The airflow through it is inefficient, and gaps in the enclosure let fumes bypass the filter entirely.

1. Set the chamber fan to 70%+ to push more air through the filter
2. Replace the stock filter every 2-3 months of active use
3. Top glass riser — improves airflow inside the chamber
4. Aftermarket HEPA+Carbon filters (Alveo3D, Scrubby mod on Printables)
5. For serious filtration: external exhaust duct

720p Camera: Dark and Grainy Image

This is a hardware limitation — the P1S camera is 720p with no built-in lighting. Bambu Studio handles the video stream worse than the Handy app. Spaghetti detection is also less accurate compared to the X1C (which has Lidar).

1. Add LED lighting inside the chamber (mods available on MakerWorld)
2. Use the Handy app instead of Bambu Studio for monitoring
3. For better monitoring: external IP camera (Obico, OctoPrint)
4. Keep the lights on near the printer — spaghetti detection needs good lighting

Auxiliary Cooling Fan Failure

Fan blades get damaged by debris or collisions, the motor wears out over time, and the cable connector can come loose from vibrations.

1. Check and reseat the fan cable connector
2. Clean the blades — remove any debris or filament residue
3. If that doesn't help: replace the aux fan (available in the Bambu Store)
4. Replacement doesn't require recalibration
5. Always power off the printer before any fan maintenance

Frame Misalignment After Shipping

The P1S frame can get knocked out of square during shipping. In some cases the diagonal difference reaches up to 8 mm, causing print asymmetry and calibration issues.

1. If you see visible misalignment: return it under warranty — don't try to fix it yourself
2. If warranty isn't an option: remove panels, square the frame using diagonal measurements (~1.5 hours)
3. Print geometry correction: M1005 command in start G-code
4. Check Y-axis belt tension after realignment

HMS Error Codes

When to Contact Support

Most P1S issues are DIY-fixable, but some situations call for Bambu Lab support. If you've got a visibly misaligned frame out of the box — don't try to fix it yourself, just return it under warranty. Same goes for persistent HMS errors that won't clear after swapping cables and fans. For comparison with other Bambu Lab printers, see our Bambu Lab A1 review and A1 vs A1 Mini comparison.

Signs of a hardware problem: constant heatbed temperature error (HMS_0300-8009), Z motor not working after clearing the rails, or control board failure. DIY repair in these cases can void your warranty. Reach out via support.bambulab.com or the chat in the Bambu Handy app.

Sources

• Nozzle/Hotend Unclogging Procedure — Bambu Lab Wiki
• What is heat creep? — Bambu Lab Wiki
• Bambu Lab Firmware Update Sparks Backlash — 3D Printing Industry
• How to Install AMS 2 Pro to P1S — Bambu Lab Wiki
• BambuLab Wiping System Guide — Makers101
• Replace the Auxiliary Part Cooling Fan — Bambu Lab Wiki
• P1 series WiFi/BT/LiveView troubleshooting — Bambu Lab Wiki
• Bambu Lab HMS Error Codes — Corb3D
• How I Created Problems with My P1S — 3DToday