Solving OKI Errors while printing “544: Invalid Y C”, “545: Invalid M C”, “546: Invalid C C”, “547: Invalid K C”, or “544:Y Invalid C”, “545: M Invalid C”, “546: C Invalid C”, “547: K Invalid C”
Posted by jpluimers on 2026/03/09
If any of the below OKI error codes occur during printing then first re-seat (unlock, then lock) the corresponding toner cartridge.
When the error reoccurs, then wear a mask (toner spills can be dangerous to your lungs), then: unlock the toner cartridge, remove it, vacuum away any of the toner spill in the printer and on the cartridge, reinsert it and lock it.
The cause is a mechanical issue that happens both when only using original OKI toner cartridges and OEM or third party ones: wear of the parts over time will spill more and more toner causing the locked cartridge detection to cause a faulty result due to excessive spilled toner build-up.
For me this mostly happens on the colour cartridges and far less often on the black cartridge.
Error code list for the message at [Wayback/Archive] Troubleshooting | OKI “Check Toner Cartridge. Improper Lock Lever Position. Error: 544, 545, 546, 547”:
- 544: Yellow (abbreviated as Y)
- 545: Magenta (abbreviated as M)
- 546: Cyan (abbreviated as C)
- 547: Black (abbreviated as K, but sometimes as B)
On the above page self the solution lists as
A color toner cartridge indicated on the screen is not installed.
Make sure that the lever on the toner cartridge is fully turned and the protective tape is removed.
C: Cyan (blue), M: Magenta (red), Y: Yellow, K: Black
What it misses is that the lock lever can be clicked into the locked position, but the detector misses the signal because of spilled toner built-up.
This is how the error codes can show on the display of OKI printers:
- my [Wayback/Archive] C332 | Colour Printers | Drivers & Utilities | OKI Europe Ltd
[Wayback/Archive] 427565409-f5210239-f418-4030-b425-6b4457925a2c.png (522×611)“544: Improper Y”
- the C332 or similar at [Wayback/Archive] oki激光打印机显示故障码CHECK TONER CART 544:Y IMPROPER C 错误 … – OKI打印机 – OA维修网 – Powered by Discuz! (The Google Translate into English: “Oki laser printer displays fault code CHECK TONER CART 544:Y IMPROPER C error … – OKI Printer – OA Maintenance Network – Powered by Discuz!”)
[Wayback/Archive] forum.php (580×1031)
“544: Y Improper”
via [Wayback/Archive] OKI打印机 OA维修网-打印机维修论坛|复印机维修论坛|速印机维修论坛|办公设备维修论坛 – Powered by Discuz!.
Related [Wayback/Archive] The complete guide to OKI Error Codes and how to fix them | okOKI
Queries:
- [Wayback/Archive] oki “improper c” – Google Search
- [Wayback/Archive] oki “544:improper” – Google Search (which for me gave way more results than the archived links)
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