Samsung CLP-320 Laser printer On switching on printer the RED light comes on troubleshooting guide indicates LSU Uint Failure #U2-1112 . I've cleaned the cartridges and the drum, the fuser is hot but i've still got the problem. The printer is 7 months hold and I've printed lessthan 300 A4 pages.

This is a overheating problem. First try this - Put astack/folded paper under the paper tray position (under the tray handle) -- tothe point that the printer weight actually sits on the folded paper instead ofon its actual foothold. If theproblem still exists, then you may need to replace the fuser. Hope this will help you. Good Luck.

Communication error between the toner cartridges and the mainboard of the printer.
Remove all the cartridges, make sure all the protection tapes are removed, that the contact pads are clean and the cartridges themselves are in good shape - no dents or deformations. Put them back correctly - make sure that they are fully inserted - and try again. If it's the same then it's time to take it to a dealer's repair shop.
Since the printer is still in the warranty period the necessary investigations can be performed only by them , free of charge. You definitely shouldn't try to do that yourself, that would void the warranty and all the repairs will be on your money.

Check your toner cartridge it must not be properly seated.once the toner is seated properly the motor that locks the toner will activates and hold the toner inplace and the sensor for the toner will be triggered and tell the motor to stop because toner is seated.once this process fails during initialization an error will occur.initialization process occurs during every power on ...observe this process during power on and you will be able to find the problem..it could be the sensor for the toner the motor or just improper placement of toner..thank you and good luck!