Hi Jack3,
This message may be resolved by resetting your PIXMA MX340. Please follow these steps:
1. With the printer powered on, open the cover. The ink will move to the replacement position.
2. Raise the cartridge locking lever on the black ink cartridge.
3. Slide the cartridge out of the holder towards you.
4. Raise the cartridge locking lever on the color ink cartridge.
5. Slide the cartridge out of the holder towards you.
6. Once both cartridges are removed, unplug the power to the printer (without turning it off).
7. Reconnect the power cord.
8. Turn on the printer.
9. Open the cover. The carriage that holds the ink will move to replacement position.
10. Make sure the orange cap is off of the bottom of the black cartridge.
11. Place the black cartridge in the printer.
12. Lower the cartridge locking lever.
13. Make sure the orange cap is off of the bottom of the color cartridge.
14. Place the color cartridge in the printer.
15. Lower the cartridge locking lever.
Close the cover. The printer should make some noise for a few moments, and then return to standby.
If the message persists, to clear the low ink warning message, press and hold down the <STOP/RESET> button for ten seconds, and then release it. This will disable the ink detection.
If you continue to have difficulties, please contact our support group using the following link:
http://www.usa.canon.com/cusa/consumer/standard_display/contact_us_consumer
