Sharp “U2-40” — waste toner full won’t reset (MX/AR series)
Joe B.
Reviewed for technical accuracy
Specialities: Sharp MFPs (MX/AR/AL), waste toner container resets, SIM/service mode, sensors (TNFD/CRUM), developer/toner systems
Sharp U2-40, waste toner full won’t reset — SIM codes, TNFD sensor/actuator flag, CRUM chip & counter
Technician
• Model (e.g., **MX-M314N / MX-3070 / AR-M236 / AR-5516**)?
• After you emptied/replaced the **waste toner box**, did the alert stay?
• Do you also see **U2-40** or just “Replace/Empty waste toner”?
• Any recent **toner cartridge** swap or message about **CRUM chip**/non-genuine toner?
• Has anyone run **service mode/SIM** (e.g., SIM 16, SIM 24-04, SIM 30-1) yet?
Technician
Meanwhile, **U2-40** is not a waste counter; on AR/AL lines it’s often a **toner CRUM communication** fault (chip on the cartridge), and on some MX units it can point to **SD system storage** trouble. That’s why the message reappears even after you empty the box — you may have two issues overlapping: the **TNFD sensor** not changing state and a **CRUM/SD-related U2-40**.
Technician
1) Open the front cover; release the latch and slide the **waste toner box** out level to avoid spills.
2) If reusing, empty outside, reinstall the bottom plug firmly; toner under the plug can keep the **optical TNFD** from toggling.
3) Inspect/clean the **actuator flag** and the **TNFD window** (no caked toner). Lightly vacuum or use compressed air.
4) Reinsert the box until it clicks; mis-seating leaves the sensor “Full”.
5) Power cycle the MFP and check if the warning clears.
Technician
• Enter **SIM/service mode** (key sequence varies by panel). Go to **SIM 30-1** (Input check) and look for **TNFD (waste toner full detection)**. Toggling the box in/out should change the sensor state.
• If the sensor doesn’t change, the **actuator** is stuck or the sensor is contaminated/faulty.
• After replacement/emptying, clear the counter via **SIM 24-04** (waste toner related) or the model’s designated maintenance SIM. Some AR models also clear via **SIM 16 (trouble cancel)** after physical fix.
• Exit SIM and reboot; the “waste toner full” should be gone.
Technician
On **AR-/AL-series**, **U2-40** commonly means **CRUM chip communication** — cartridge chip not read. Reseat or replace the cartridge with known-good OEM; check the **rear connector** for bent pins. Then run **SIM 16 (trouble clear)**.
On certain **MX-M** models, **U2-40** can be **SD data area** error. Power cycle to trigger an auto-rewrite; if it recurs, the **SD card** or **MFPC PWB** may need replacement. In that case, don’t loop SIM clears — address storage hardware.
Technician
• Always replace or fully empty the **waste toner container** level; seal the plug cleanly.
• After replacement, verify **TNFD** state in **SIM 30-1** and then clear the relevant **counter** (SIM 24-04 or model-specific).
• Keep the cavity dust-free; a film of toner on the **optical sensor** can retrigger “Full”.
• Stick with **genuine or compatible cartridges with proper CRUM**; mismatched chips can re-raise **U2-40** and block prints.
• If you ever see **U2-40** on an MX storage-based model, check **SD/HDD health** before repeated resets.
Technician
Quick answer: the accepted fix
Accepted fix when a Sharp says “Waste toner full” and won’t clear: reseat/clean the waste box and actuator, confirm the TNFD sensor in SIM 30-1, then reset the waste counter (e.g., SIM 24-04 / model-specific). If U2-40 persists, address the separate fault — typically a CRUM chip issue on AR/AL models (replace toner and run SIM 16) or an SD system error on certain MX units (storage/PWB check).
Why “waste toner full” and U2-40 are different alerts
“Waste toner full” is driven by the TNFD sensor and a maintenance counter tied to the waste toner container. The **U2-40** trouble code is a separate fault that varies by series: often a CRUM communication error (toner chip) on AR/AL models, and an SD data area fault on some MX MFPs. Clearing the waste box alone won’t remove U2-40, and clearing U2-40 won’t reset the waste toner counter.
How to confirm the reset worked
After you clear the counter and the panel shows Ready, print a **configuration list** and a **test page**. Recheck **SIM 30-1** to verify **TNFD** changes state with the box in/out. If the panel re-reports “Full,” clean the **optical window** and reseat the **actuator flag**; if **U2-40** returns, inspect the **toner cartridge connector** and, on MX models, run diagnostic steps for **SD/HDD** integrity.
Sharp U2-40 / waste toner — quick troubleshooting tips
Most “won’t reset” cases are sensor state not changing or the wrong SIM cleared; U2-40 is usually a separate CRUM/storage fault.
Quick path: reseat/clean the **waste toner container** → verify **TNFD (SIM 30-1)** → clear the **waste counter** (SIM 24-04 or model procedure) → if **U2-40** remains, reseat/replace the **toner (CRUM)** and run **SIM 16**, or check **SD system** on MX models. This resolves the majority of Sharp **MX/AR** “waste toner full won’t reset” scenarios.
Disclaimer: This information is AI-generated and intended for general guidance only. For advice specific to your environment, please consult a verified expert on Whizz-Tech before making decisions.
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FAQ
Does U2-40 mean the waste toner box is full?
No. **U2-40** is not a waste counter. On many AR/AL models it indicates a **CRUM (toner chip) communication** error; on some MX units it points to **SD data area** trouble. The “waste toner full” alert comes from the **TNFD sensor** and a separate counter.
How do I reset “waste toner full” on a Sharp MFP?
Replace/empty and **reseat** the waste toner container, clean the **actuator/optical window**, verify **TNFD** in **SIM 30-1**, then clear the **waste toner counter** via SIM 24-04 (or the model’s maintenance SIM). Power cycle and recheck.
What clears U2-40 on AR-series machines?
Use a known-good/OEM **toner cartridge** (CRUM), inspect the rear connector for bent pins, then run **SIM 16 (trouble cancel)**. If your MX shows U2-40 tied to **SD storage**, address SD/HDD/PWB per service guidance instead of repeatedly clearing.
Sources
- PrintCopy.info — Sharp U2-40 (AR-series: CRUM communication, SIM 16 remedy)
- Copytechnet — Sharp MX: check TNFD waste-toner sensor via SIM 30-1
- EquipMyBiz — Sharp waste toner box emptying & reseating process
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