asked Feb 21, 2006 at 4:10pm
Unknown Printer

Okidata C5151 541:M Toner Sensor Error

I have an Oki C5150 color laser. It has 2 problems, the main one is the 541:M Toner Sensor Error. This usually comes up during initialization, sometimes it does OK. When it does init ok, the black print is faded out toward the left side of the page.

The magenta toner is around 1/2 way full, so the error isn't due to it being empty. I've also taken the toner/image assembly & swapped it with one of the other assemblies, just to check the sensor itself. Where ever I put the magenta, the error follows(like if I put the magenta in for the cyan, & cyan in for magenta, it gives me a 541:C error). Am I looking at a bad toner cart causing my problems?

Any help or suggestions are appreciated!
I'm new to this machine, too, but saw the same error. The customer had another toner - no luck. They had another C5150, so I went whole hog replacing boards. First the sensor board, then the print engine controller (right-front), then the brains (right-rear). Still no good. The toner sensor error finally went away when I put their old drum back in. The Black Toner Sensor Error had shown up a few days after replacing their black drum. Since then I've read another post on this forum about resetting the consumables counters. I found it with a search for "5150" from the home page here. I hope that will allow me to use the new drum, but haven't been back yet.
by Eric Sandbo on May 15, 2006 at 12:08pm Add comment
Hi, I've got the same error. After replacing the K-Drum for the first time, the printer worked for 1 day and suddenly displayed "543 K Toner Sensor Error".

I replaced the Toner Cartridge with a new one, but without any success.
I 've put the K drum unit + toner in the Magenta slot and the error now was M Toner Sensor Error.

So, i concluded that the error resulted from the DRUM. I replaced the K drum with another new DRUM and YES, it worked.... for 2 days.. then again "K TONER SENOER ERROR" reappeared and the printer wouldn't print anything.

I 've read in this forum about disbabling the sensor. So i did this. The error was gone! BUT.. the printouts were empty. Nothing was printed on my paper :(

Could it be possible that i had 2 defective DRUMS? Should i replace the drum again (expensive) and hope the error stays out?

OR does anyone know what to do about this error?

I've contacted OKI helpdesk, but the only thing they could tell me was to try all the things that i've tried already myself.

Please help!

- jbamps
i have two oki color printers - c5100 and c5250

the toner sensor error happens to me quite frequently too.

i found out that the problem is the toner cartrige itself.
inside the lock of the toner cartrige (the red handle on the
right side of the toner container; sometimes its blue)
there is a white piece of plastic within a hole at the side.
during warmup or even during printing this white plastic piece
turns upwards and gets stuck in upwards position inside the handle.

to solve this problem temporarily i just open and close the
handle and check that the white plastic is back down.

the real solution is to replace the toner cartrige.

very ennoying if the cartrige is new or only half spent.

especially ennoying is that while printing this toner sensor
error stops the printer and the toner and drums have to be
removed in order to take out the stuck paper.

if this is such a frequent problem oki could at least let
the printer in case of toner error eject the paper thats on
the way.
by hazzardazzle on Jun 11, 2006 at 10:58pm Add comment
I am having this trouble also. I checked the piece of plastic, its alright, the cartridge isn't empty. Would you have an idea as to what to do, other than throw this out the window?! - cherrijones
1. Turn machine on while pushing and holding the (+/-) menu buttons at same time.
2. Menu window will show "OKI USER"
3. Scroll to " Engine Dialog Mode" is indicated. Push Enter button.
4. "Diagnostic Mode xx.xx.xx S-Mode is indicated.
5. Press (- or +) button until (“ENGINE = PARAMETER SET 2”) is displayed.
6. Push Enter button
7. "TONER SENSOR = ENABLE" is displayed.
8. Push Enter button
9. Press (- or +) "TONER SENSOR = DESABLE" is displayed.
10. press "ON-LINE/CANCEL" buttons at same time.
11. (*) is displayed.
12..... READY
by unknown on Jul 22, 2006 at 10:14am Add comment
That worked.

Thanks - Anonymous
Thank you! Thank you!

When the computer is reporting a false error, tell the computer to stop reporting! This solved my problem! Thank you! - Anonymous
yea, Leos! - Anonymous
Thanks bro!!! It worked for me.... - Anonymous
Thanks a million. This worked great for us. You might add that they need to turn the printer off and then back on to finish the process.
- Anonymous
Leos, I did what you said in your post and the printer´s sensor error finished, but when I tried to print a single page it was completely black.

My printer is OKI C5250. - Anonymous
Thanks, Leos. This solution solved a problem that has plagued me for a long time. One tweak, however: Step 12 for me was to turn the machine off and on again because I couldn't get printer to go back to on-line/ready status. - unknown
I did the steps to disable the sensor error message, but how do you get to ready - Anonymous
This worked beautifully for me! I've printed a hundred + pages without any problems whatsoever! THANK YOU, THANK YOU! - Anonymous
sorry to disapoint you all but the toner sensor error is related to the agitator inside the toner cartridge, it occasionally falls out of its housing so it does not move the toner sensor which is the white plastic piece that bobbles up and down on the coloured handle, the toner sensors themselves see this white flag if it dosnt move the machine thinks the sensor is broken so toner sensor error is flagged, if the flag moves too quickly the machine thinks the toner is empty.
by tonyuk on Nov 20, 2006 at 1:34am Add comment
I had the same problem with the toner sensor error. I actually have the c5150 and went to the following URL that alerted me how to use a cotton swab to clean the sensor and now it works beautifully without haveing to disable the sensor.. Go to the following website for instructions and photos.

by kelescam on Dec 18, 2006 at 1:05pm Add comment
This works really perfect :-) Thanks - unknown
I got to give kelescam all the credit (8th post from the top).

I have an OKI C5150 and replaced my black toner today. I got the dreaded K Toner Sensor Error message. I tried another old toner and the error wouldn't go away. I got nervous thinking I had broken something and considered how much it would take for a technician to service my beloved printer.

Thanks to this forum and by following his advice listed in the following link; I used a cotton swab to clean the sensor on both the toner and the printer (make sure you clean the right sensor as pictured in the link). It worked wonderfully without having to disable the error in the system. Here's the link once again:


Quiquito - unknown
Have a okidata c5100 that seems to print only black when it wants. Customer installed a new black toner and machine ran fine for part of the day. Then it just quit printing black. The colors still print fine and there are no error messages. She shut machine off and left it overnight and the printer printed black for part of another day. Happened with a new toner and with the old toner. HELP
by zooker on Jul 19, 2007 at 1:31pm Add comment
I run a new number plate business of my oki 5250 printer, ive just bought it second hand, everything is working fine apart from when i print onto the plastic strips for number plates the end colour printing results have a very faint sheen of yellow on them, ive cleaned all inside printer and cartridges but problem still exists, anybody know how to resolve this problem, please.
by unknown on Oct 13, 2007 at 3:14pm Add comment
Thanks had a lot of similar problems on an OKI C3200 did the engine dialog mode trick to disable the toner sensors and it seems to have solved a very annoying problem. It's stopped nagging me about the toner level being low as well but since I don't do any long print runs this is also a blessing!
by unknown on Apr 29, 2008 at 1:23pm Add comment
I've also got an OKI C32000 with the same problem but I wonder what Dialog Trick are your refering to. My Oki only has an Online and a Cancel button to play with. How do you get into this dialog mode?
Thanks a lot - Anonymous
Hi there! Had the same error on the C3400 model. My easy fix was found thanks to some smart Brits who posted it on their Oki site. There is a little sensor on the blue plastic lock on the right hand side of the toner. It's a little open square, that lines up with a little square cut into the metal inside of the printer. If it's clogged with toner or dust, the sensor can't be read, hence the message. Just take an air duster, give it a quick blast on both the toner cartridge and the side of the printer, and that worked for me.

by unknown on May 2, 2008 at 7:42pm Add comment
thanks for your post, it got me working. - Anonymous
I have a C3400n printer and am getting so frustrated with the toner sensor error. I have tried taking out the cyan toner and drum assembly, but I am lost when I try to find the parts refered to in a picture description for cleaning the sensors.

Any help? I need to print a bunch of stuff for our school and cookbook we are selling and am stuck totally!

Also, any directions for resetting the drums in a C3400n?

Thanks in advance for any and all help! I appreciate it! - Tree in KY
I disabled sensor error on my C5250 and in now works! Many thanks. Patrick
by unknown on Jun 15, 2008 at 3:42am Add comment
A customer is gettnig a toner low after refilling a B4400 toner cartridge. Any tips?

by unknown on Jun 16, 2008 at 2:21pm Add comment
I'm completely guessing:

1. Turn the printer off and back on, off course
2. Make sure the cartridge is filled to the top and that the toner is evenly spread out?
by unknown on Jun 16, 2008 at 2:32pm Add comment
by fotinos on Oct 8, 2008 at 4:10am Add comment
The B4600 Image Sensor is hiding, but with a lot blowing out with an air hose, the problem finally went away.
by Anonymous on Dec 12, 2008 at 2:53pm Add comment

by Anonymous on Dec 21, 2008 at 5:39pm Add comment
by Anonymous on Feb 26, 2009 at 6:19am Add comment
After replacing drum and installing fuse in all colour drumkits monitor for OKI C3200 gives "Toner Sensor Error (Yellow)" message. When I change Yellow/Cyan place it says error for Cyan - so with Yellow is something wrong. I've checked fuses, no one blows up as they should to reset drums counters.
Anybody know how to resolve this problem, please.
by unknown on May 15, 2009 at 6:48am Add comment
Hi, We have come across this on the C3300N & C3400N printers and have found it to be a small cover not opening when you install a new cartridge, to fix this remove the offending toner cartridge and drum as one unit,just lift the toner cartridge without unlocking it and it will bring the drum out with it, turn the drum & toner 90\% to look at the right hand end, you will see below the 2 copper contacts a small rectangle, make sure you can see the green circuit board and white diode through the rectangle, if not use a pen to move the black cover so the hole is clear --- be careful not to touch the diode or circuit board with the pen --- reinstall the toner cartridge and drum. This should fix the problem for that cartridge however you may need to do this every time you replace a toner cartridge in said drum.
Hope this helps.
by WaddyNZ on May 19, 2009 at 4:45pm Add comment
Thanks a lot! I did as you advised and now it works! - Anonymous
THANK YOU THANK YOU THANK YOU! This saved me a lot of money! Everytime my printer is not being used for a month or two this happens, and i send it in for repairs. This time, I didnt have the time to do so, and started googling this error! I dont know how to thank you enough! thank goodnes, i dont have to send it in ofr repairs and walk out with a R800 service bill! THANK YOU SO MUCH!!!!! - Anonymous
THANK YOU THANK YOU THANK YOU! This saved me a lot of money! Everytime my printer is not being used for a month or two this happens, and i send it in for repairs. This time, I didnt have the time to do so, and started googling this error! I dont know how to thank you enough! thank goodnes, i dont have to send it in ofr repairs and walk out with a R800 service bill! THANK YOU SO MUCH!!!!! - Anonymous
Greetings a customer has a Oki c5250n Printer. 3 days ago i changed the drum and a high capacity toner. The printer was working for 2 days and now he is getting the sensor error from black toner. What can i do?

Thanks in advance
by unknown on Jun 9, 2009 at 5:28am Add comment
I'm using a OKI C3400 and I get the Toner Sensor Error every times I change the toner. If stand in front of your printer and take out one drum (not only the toner but the entire drum), you're going to see a little square hole on the right side of the drum with a piece of plastic that goes up and down. I fixed my problem using scotch tape to make it stay up. Since I did that with all 4 drums. I never got this message.

Maybe we can just take out the plastic part that goes up and down but I don't want to risk a drum so scotch tape is my savior :P

Hope this can help others.

J. Bonnier
IT m0851
by Anonymous on Aug 14, 2009 at 7:25am Add comment
Thanks so much!!! Your idea on taping the square hole on the drum worked!! Thanks again - Anonymous
Like all of you I had the same sensor error.

I have a C5150n. My sensor error was bouncing around between different cartridges in my printer. I tried the cotton swab and the compressed air solutions. Unfortunately, none of these solved the problem for me.

What did work was Leos's solution in going into diagnostic mode and turning off the toner sensor. After a restart it worked fine.
by aclark on Sep 13, 2009 at 11:13am Add comment
I have an earlier model, c3200 with the same 543k error. Using a new toner cartridge, I shook the cartridge hard a few times to loosen up the toner in the cartridge. Put it back and everything works fine.

My guess is the supplier of the toner had it sitting around for awhile and/or in heat. Shaking the toner loose enabled the sensor flag loose.
by unknown on Sep 28, 2009 at 5:16pm Add comment
Bless you, Leos!

I disabled the toner sensor per your simple instructions, and all cartridges work fine on my C5200 Okidata!

What a pain it is to get the error message, try out new cartridges, and still not be able to print because the error message (541) won't go away...

I wonder if it's because some of us use generic toner cartridges, rather than Oki ones? I didn't have a toner sensor problem until I tried out a generic cartridge. Is the configuration different???

by unknown on Oct 15, 2009 at 11:31am Add comment
Yet another person chiming in to say thank you, not just to Leos but to everyone who provided insight into this problem. I ended up swapping out the toner for the sake of simplicity, but it appears that the white sensor tab on our toner had been dislodged, which would explain the problem.
by Anonymous on Feb 17, 2010 at 8:04am Add comment
Thank you J. Bonnier. I have a C5400 with an annoying sensor error. On the right side of my drum on the blue lever is a rectangular hole with a silver plastic door that will slide up. First I tried taping the door "up" and open. That produced even more sensor error messages. Next I just taped over the rectangular hole. Works great. Thanks a bunch.

I wonder if there's a long-term problem with this fix.

by Anonymous on Mar 3, 2010 at 4:34pm Add comment
Hello again. I spoke too soon. Initially after taping the doorway closed, it worked fine. Then no matter what I tried with tape - I was getting error messages. I tried removing all tape and simply rotating the blue levers back and forth, and now it seems to be working great. Good luck.

by Anonymous on Mar 3, 2010 at 5:00pm Add comment
Oki C5600 toner to remove the new toner M. I set the alarm again M empty, I just have to ask the how,
by Anonymous on May 25, 2010 at 12:14am Add comment
tengo una oki c3200 con el mismo error de sensor que todos como puedo anular dicho sensor?
by unknown on Sep 10, 2010 at 3:25pm Add comment
Disabled the damn sensor and viola' the problem ceased. Thanks to this forum...

by unknown on Aug 25, 2011 at 12:47pm Add comment
Hi everybody,

I've the same problem with MC561. Does anyone know how to reset the toner sensor?


by Naeem_f on Oct 10, 2011 at 11:00am Add comment
Hi everybody,

I've the same problem with MC561. Does anyone know how to reset the toner sensor?


by Naeem_f on Oct 10, 2011 at 11:03am Add comment
PEOPLE! When you say "this works" or "it works", etc., PLEASE also mention WHICH TIP worked. There are several suggested in the thread above your post. I'm tired of having to guess which one worked for you. Your "it worked" post doesn't necessarily come RIGHT after the suggestion post you're referring to.
by mtnmedic on Oct 13, 2011 at 1:24pm Add comment
I disabled the toner sensor alerting using the steps leos posted above (dated 7/22/06). Now the error is gone and I'm able to print again. Thank you, leos. However, if this fix is going to interfere with my ability to determine if a toner cartridge is getting too low/empty, I'll have to check out the other "fixes" that deal with cleaning the sensor, doing something with the little tab, etc. on the cartridge itself.
by mtnmedic on Oct 13, 2011 at 1:47pm Add comment
Hey everybody,

I have the same problem with the Toner Sensor Error on OKI B4600. I just replaced the old toner with a and new one and I tried some of the offered solutions but the error still occurs.

I tried to insert another drum and the error disappears, but I had the same problem 6 months ago when I bought a new drum and now is its capacity to 60\% so I think that it is not cost effective to buy new drum again

Does anyone know is there a way to solve this problem without re-buying a new drum.

Best Regards

by sandrara on Mar 27, 2012 at 11:32pm Add comment
I have a c5800 giving me the same problem (error 543 Toner Sensor Error), I've cleaned it and disabled the sensor, but noting happened. Any other suggestions??? Thanks
by shydee37 on Jul 23, 2012 at 6:15am Add comment
Has anyone heard about a program called "Oki maintenance utility" ? It allows you to control and set many oki printers parameters, including disabling toner sensor error (this option isn´t available for C3200 no LCD , which i desesperately need ¡¡¡¡ )
by unknown on Jan 17, 2013 at 1:54pm Add comment
So actually, there is a sensor on the printer that is supposed to pick up whether or not that little piece of plastic on the cartridge is there. It turns out that little sensor EASILY gets toner on it and becomes blocked. A thorough blast from some Pressurized air did the trick for me.
by unknown on Nov 11, 2013 at 10:15am Add comment