Kyocera error code
C7990Waste toner box full detected
✅ You can try a fix
What it means
The machine has detected that the waste toner container is full and stops to avoid spilling toner inside.
Common causes
- Waste toner box full and due for replacement
- Waste toner sensor dirty or faulty
- Box not seated correctly
What you can safely try
- 1Remove the toner cartridge, shake it gently side to side and re-insert it until it clicks.
- 2Check the waste toner box — replace it if it is full.
- 3Use the toner made for your exact model; a wrong or refilled cartridge without a working chip often causes this code.
- 4Switch the machine off, wait 30 seconds and switch it on again — note whether the code comes back.
⚠️ If the code comes back after a restart, stop using the machine and call an engineer — running it on can damage more parts.
The exact meaning can vary slightly between models. Send us the model number for a precise diagnosis.
