My T630 Printer while printing suddenly stops and message 929 SERVICE TONER SENSOR message pops up. It happens a lot now . I have to clear blocked paper out of printer then turn printer off and on again to clear message, any suggestions what i need to do to clear this error

A 929 Service Toner Sensor error indicates a problem with the toner sensor, the front harness cable, or the developer drive. It could also mean that the toner cartridge is defective.

• Take the cartridge out of the printer and locate the encoder wheel on the right-hand side of the cartridge. The encoder wheel can be found on the right side of the cartridge (usually over a bar code sticker). It is a thin, black, plastic wheel with small rectangular notches cut into it. This wheel will sometimes get stuck, but you can free it by turning it by hand.
  
• Try moving the wheel forwards and backwards a little. If it does not turn correctly, you will receive a 929 Toner Sensor error on the printer when you try to use the cartridge it is attached to. Note: The encoder wheel moves only a little bit each way. It should not make a complete revolution. If it does, the wheel is probably broken.
  
• Try to move it a little bit each way a couple of times to see if you can free it up. Caution! DO NOT force the wheel as you could break it.
  
• If the wheel on the toner cartridge is stuck, try another new toner cartridge. ( If you do not have another new toner cartridge available, an old toner cartridge or another cartridge from a working printer of the same model will also suffice for this test.) Power the printer off and install the second toner cartridge. Then power the printer back on. If another toner cartridge clears up the 929 error, the printer is fine and the problem is with the toner cartridge. If the error does not clear, there may be a problem with the printer.
  
• If you narrow down the problem to the toner cartridge, call the point of purchase and explain the situation to them. They may have a replacement policy. If they cannot help you, call our Technical Support Center and we will see what we can do to replace the cartridge that is causing the error. We will not be able to reimburse the price of the cartridge, but we can offer you an exchange. To do this, we may ask you to send in your cartridge first. Please note that we cannot offer an exchange on a refilled or refurbished cartridge. For this, you must go through the point of purchase.
  

If you need further assistance contact Lexmark Technical Support.

Hello thanks for using Fixya

A 929 Service Toner Sensor error indicates a problem with the toner sensor, the front harness cable, or the developer drive. It could also mean that the toner cartridge is defective.
The most likely cause of this error is the toner cartridge itself. This is especially true if it is a new cartridge and the error started after you installed it.
To solve it try this:

Take the cartridge out of the printer and locate the encoder wheel on the right-hand side of the cartridge. The encoder wheel can be found on the right side of the cartridge (usually over a bar code sticker). It is a thin, black, plastic wheel with small rectangular notches cut into it. This wheel will sometimes get stuck, but you can free it by turning it by hand.
Try moving the wheel forwards and backwards a little. If it does not turn correctly, you will receive a 929 Toner Sensor error on the printer when you try to use the cartridge it is attached to
Note: The encoder wheel moves only a little bit each way. It should not make a complete revolution. If it does, the wheel is probably broken.
Try to move it a little bit each way a couple of times to see if you can free it up. Caution! DO NOT force the wheel as you could break it.
If the wheel on the toner cartridge is stuck, try another new toner cartridge. ( If you do not have another new toner cartridge available, an old toner cartridge or another cartridge from a working printer of the same model will also suffice for this test.)
Power the printer off and install the second toner cartridge. Then power the printer back on. If another toner cartridge clears up the 929 error, the printer is fine and the problem is with the toner cartridge.
If the error does not clear, there may be a problem with the printer.
If you narrow down the problem to the toner cartridge, call the point of purchase and explain the situation to them. They may have a replacement policy.
If you receive this error with a second toner cartridge, you may want to check if the Front Harness Cable is plugged into the Toner Sensor then Do the following:

Turn off the printer and remove the toner cartridge.
Look inside the printer at the place where the cartridge goes (on the right). You should see the Toner Sensor. On the back of the sensor assembly, you should be able to see a white cable connector.
Push this white cable connector into the toner sensor assembly by pushing the connector towards the front of the printer.
If you continue to receive the 929 error the final option is your printer will probably need service.


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First, replace the toner. If that doesn't fix the issue the print head needs to be changed most likely.

Hi,

Please follow the solution in the link below. Also as you putting in the cartridge always check for loose toner in the area and on the cartridge itself as this can block the sensors.

http://www.support.xerox.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=74,E=0000000001343666831,K=8485,Sxi=0,Case=obj(3510)

Niallbt

Hopefully this will clear up a little confusion I had:

1. Follow instructions for replacing toner cartridge.
2. Remove drum from printer. Take care not to handle the drum surface. Look for a small rectangular window or depression. The window will be completely or partially blocked by a flap.
3. Use a fine pointed instrument to move the flap up, so that the sensor underneath is visible.
4. Replace the drum. The error should clear after the print engine has reset.

Hi Tony

you can refer to this links

http://support.lexmark.com/perl/support/support.cgi

929 or 929.xx Service Toner Sensor Error on a Lexmark T64x Printer

Error: " 929 Toner Sensor "


"927, 928, or 929 PC Cartridge Error" on the Lexmark W820


Error: "929 Service Toner Sensor"

Error: 929 Toner Sensor

A 929 Service Toner Sensor error indicates a problem with the toner sensor, the front harness cable, or the developer drive. It could also mean that the toner cartridge is defective. 
The most likely cause of this error is the toner cartridge itself. This is especially true if it is a new cartridge and the error started after you installed it. 
Take the cartridge out of the printer and locate the encoder wheel on the right-hand side of the cartridge. The encoder wheel can be found on the right side of the cartridge (usually over a bar code sticker). It is a thin, black, plastic wheel with small rectangular notches cut into it. This wheel will sometimes get stuck, but you can free it by turning it by hand.  
Try moving the wheel forwards and backwards a little. If it does not turn correctly, you will receive a 929 Toner Sensor error on the printer when you try to use the cartridge it is attached to. Note: The encoder wheel moves only a little bit each way. It should not make a complete revolution. If it does, the wheel is probably broken. 
Try to move it a little bit each way a couple of times to see if you can free it up. Caution! DO NOT force the wheel as you could break it. 
If the wheel on the toner cartridge is stuck, try another new toner cartridge. ( If you do not have another new toner cartridge available, an old toner cartridge or another cartridge from a working printer of the same model will also suffice for this test.) Power the printer off and install the second toner cartridge. Then power the printer back on. If another toner cartridge clears up the 929 error, the printer is fine and the problem is with the toner cartridge. If the error does not clear, there may be a problem with the printer. 
If you narrow down the problem to the toner cartridge, call the point of purchase and explain the situation to them. They may have a replacement policy. If they cannot help you, call our Technical Support Center and we will see what we can do to replace the cartridge that is causing the error. We will not be able to reimburse the price of the cartridge, but we can offer you an exchange. To do this, we may ask you to send in your cartridge first. Please note that we cannot offer an exchange on a refilled or refurbished cartridge. For this, you must go through the point of purchase.
Click here to order toner cartridges and other supplies for your printer.
If you receive this error with a second toner cartridge, you may want to check if the Front Harness Cable is plugged into the Toner Sensor. Do the following:
  
Turn off the printer and remove the toner cartridge. 
Look inside the printer at the place where the cartridge goes (on the right). You should see the Toner Sensor. On the back of the sensor assembly, you should be able to see a white cable connector. 
Push this white cable connector into the toner sensor assembly by pushing the connector towards the front of the printer. 
If you continue to receive the 929 error, your printer will probably need service. 

Source: Lexmark KnowledgeBase

The problem is caused by one of the following (normally it's the cartridge that's faulty, very common on Lexmark's and IBM Infoprints)

The toner sensor is not operating properly, the developer
drive assembly is not operating properly or the print
cartridge is defective

well i was having the same problem and what i did was open up the side of the printer. the same side that the toner sensor is on. the sensor consists of three metal parts. i took a screwdriver and pressed them on the outside. i pressed them in and up to ensure that the sensors are connecting. and i have not had that problem since.