What cause a sony bravia kdl-46xbr4 to have a dark vertical line ?

SOURCE: I have a Sony Bravia KDL-46Z4100 46' I have a green vertical line

this is probly the lcd control module unfortunatley it comes with a new lcd panel
change these.

SOURCE: Sony Bravia KDL-46V3000

turm on the tv for at least 24 hours with rf signal it will automatically get ok.

SOURCE: Sony Bravia KDL-40S2000 thin vertical line

If the line is present in all inputs and modes, there is a problem with the LCD Panel. The only way to fix it is to replace the whole LCD Panel which is very expensive (usually around $1000+ for 40" Sony). Unless the TV in under warranty, it is usually around the same price for a new TV.

Testimonial: "Thanks for the response. The service company Sony recommended told me it was probably the screen, too, and they quoted $1000."

SOURCE: A fine green vertical line displayed on the Sony Bravia 46.

Thats a pixel data problem, there's no data being sent to that row of pixels so they don't change color. This is a pixel address registry (PAR) issue and the PAR circuits need to be serviced its usually due to open or shorted SMT components on the PAR circuits. PAR also sends data, voltage, and control to each pixel, the green line you see are pixels that have voltage but because there's no data sent too them their all green because there's no control. If the pixels have voltage but no data or control they show up as green red, blue, yellow, or whit line vertically down the LCD panel. The vertical-horizontal section of PAR are controlled by 16 to 32 bit micro-controllers which may need replacing. If its under warranty take it back if not have your local repair center fix the tv for you...

SOURCE: sony bravia kdl 32l4000 - color bars running vertically on screen

In most cases is the screen is covered with vertical lines all the way accross the screen then the T-Con module is at fault. The t-con board is replaceable without having to replace the entire LCD panel which would usually make it cheaper than replacing the TV. The part number I come up with is 1-857-213-11. Please take a moment to rate my answer. Thanks...