Develop C2551 error: what it means
C2551 means the cyan toner-density sensor in the developer unit is reading outside its normal range.
What C2551 means
Each colour has a sensor that checks how much toner is mixed with the developer inside the machine. C2551 is raised when the cyan sensor reports a value outside the normal range, so the machine can no longer be sure it is printing cyan correctly and stops until it is checked. It is usually a developer or toner-supply problem rather than something wrong with your files.
Applies to: Develop ineo and Konica Minolta bizhub colour machines. The exact wording of a code can differ between models.
Common causes
- The cyan developer (imaging) unit is worn or near the end of its life
- The cyan toner is empty, or is not feeding into the developer unit properly
- The sensor is dirty, or its connection has worked loose
- Toner that is not suited to the machine
What you can safely try
- Switch the machine off at the power button, wait about 15 seconds and switch it back on.
- Make sure every door and cover is fully closed.
- If the panel shows cyan toner as low or empty, replace the cyan toner cartridge and try again.
- Note whether C2551 returns immediately or only after printing, and tell the engineer.
Don't open the machine or touch the fusing unit. It gets very hot and has live parts.
When to call an engineer
If C2551 returns after a restart, call an engineer. Clearing it normally means checking or replacing the cyan developer unit and re-running the machine's toner adjustment, which is done in service mode.
Stop being the person who deals with fault codes
On a CBE lease we can keep an eye on your machine remotely, so we often know about a fault before you do, and an engineer can be with you fast. You also get a 3-hour engineer response. Already in a contract? We can buy you out.
Remote monitoring only picks up some error codes, not all of them, so we can't promise to spot every fault before you do. Ask us which ones apply to your machine.
Frequently asked questions
Will switching off and on clear C2551?
Sometimes. A restart clears a one-off glitch, but if C2551 comes straight back the machine has found a real fault and needs an engineer.
Is C2551 caused by using the wrong toner?
It can contribute. Toner that is not matched to the machine can upset the toner-to-developer balance, so use the correct toner for your model.
Can I keep using the machine with a C2551 error?
Usually not. The machine normally locks out printing until the fault is cleared. Try the safe checks on this page once; if C2551 returns, stop and call an engineer rather than forcing it.