Alarm: UO71 more that none ink tank...

http://damnprinter.com/226/canon-service-call-errors.html
http://www.fixyourownprinter.com/forums/inkjet/26091
You need to clean your waste ink i think. For troubleshooting purposes, please perform the following:
1. Open the printer and remove all ink tanks.
2. Insert a single ink tank in the printer then close the cover.
3. Confirm whether the printer recognizes the installed tank
properly. If it does, it will indicate it does not detect the other ink tanks, as
they are not currently installed in the printer.
4. Repeat steps 1-3 with another ink tank.
5. If the printer at any time indicates two of the same ink tanks are
installed, the cause will be the last tank installed. For example, if
you inserted an ink tank earlier, and you later inserted another ink
tank, and it said two of the same inks were installed, the cause of
the issue is the last ink tank.

Hi there

For troubleshooting purposes,
Perform the following:

1. Open the printer and remove all ink tanks.

2. Insert a single ink tank in the printer then close the cover.

3. Confirm whether the printer recognizes the installed tank
properly. If it does, it will indicate it does not detect the other ink tanks, as
they are not currently installed in the printer.

4. Repeat steps 1-3 with another ink tank.

5. If the printer at any time indicates two of the same ink tanks are
installed, the cause will be the last tank installed. For example, if
you inserted an ink tank earlier, and you later inserted another ink
tank, and it said two of the same inks were installed, the cause of
the issue is the last ink tank.



Please come back and just gave a vote, it will gave me some satisfaction to know am helping some one so I will keep on helping.
All The Best: Pineworks

Thats a defective cartridge, you need to replace the one whose light is out when they come to the center. Canon will replace defective cartridges for 30 days after purchase.

You have a defective ink cartridge, usually the one whose light doesn't light when the carriage comes to the center position.

Here's what you can do....

METHOD #1 - Easiest, but it disables the ink tank level indicators.
1) Ignore the low ink indicator, and press the RESET BUTTON to continue printing. If you press and hold the reset button for 5+ seconds, it will disable the counter for that particular ink tank. Refill tank now.

2) Repeat as needed.
You will get a dire warning that this will void you warranty, blah blah blah. If you do need to take your printer in during warranty and you've disabled ink tank counting, simple reset the entire printer as describe below for the wate tank warning, and nobody will ever know. SAVE YOUR CANON CARTS with a bit of ink left in- your printer will need to have Canon carts installed for warranty service.

3) Eventually you may be warned that the tank is empty. Press reset as above to disable and continue printing.

If you think this entire thing is ridiculous- you are right.
Get an earlier model that takes un-chip carts, like an ip6000, or ip3000, or i960. Much simpler and you get to use the ink tank indicators after refilling.

************

You can reset the entire printer with the WASTE TANK reset (below) when you need to clean or change the waste tank PAD (its really not a tank) See the above instructions for the i960 and similar for other Canon printer waste tank changes.
Here's the ip4200 reset options:
1) With the printer power turned off, while pressing
the Resume/Cancel button, press and hold the Power
button. (DO NOT release the buttons. The Power LED
lights in green to indicate that a function is
selectable.)

2) While holding the Power button, release the
resume/Cancel button. (DO NOT release the Power
button.)

3) While holding the Power button, press the
Resume/Cancel button 2 times, and then release both
the Power and Resume/Cancel buttons. (Each time the

Resume/Cancel button is pressed, the Alarm and
Power LEDs light alternately, Alarm in orange and Power
in green, starting with Alarm LED.)

4) When the Power LED lights in green, press the
Resume/Cancel button the specified number of
time(s)
setting).

Time(s) LED indication Function Remarks
0 times Green (Power) Power off When the print head is

not installed, the carriage returns and locks in the

home position capped.
1 time Orange (Alarm) Service test print .
2 times Green (Power) EEPROM information print
3 times Orange (Alarm) EEPROM initialization
4 times Green (Power) Waste ink counter resetting
5 times Orange (Alarm) Destination settings After
entering the destination settings mode, press the
Resume/Cancel button the specified number of time(s)

to select the destination. For detail, see
"Destination settings procedures" below.
6 times Green (Power) Print head deep cleaning
(Cleaning of both black and color)
7 times Orange (Alarm) Reserved
8 times Green (Power) CD / DVD check pattern
9 times Orange (Alarm) CD / DVD print position
correction (horizontal: X direction)
10 times Green (Power) CD / DVD print position
correction (vertical: Y direction)
11 to 13 times Orange, Green, Orange(Alarm,
Power,Alarm) Return to the menu selection
14 times Green (Power) Left margin correction Not used

in servicing.
15 times Orange (Alarm) Return to the menu selection

I get the same error message. I pull out the yellow cartridge and put it back in. It will print a couple of times and I get the same message. Need a permanent fix.

i had the same problem and when i checked inside to see why it was not working with the cyan i saw that a sensor was the problem... it had fallen out. check it out and let me know if it is the same with yours.

Had the same error after replacing my black ink om my MP830.(UO71) I Put some Methylated Spirits on a cotton tip and gently cleaned the cartridge chip (allow it to air dry). This fixed my problem!

sometimes when you change your ink it doesnt register.hold down the stop/reset button and it will bypass that

Canon Technical Support team will be able to help here. This seem a common problem with the printer firmware.