B0490Display Backlight Circuit
- Generic OBD-II code · Body
- How the car detects it
- B0490 is not listed in any accessible J2012 source, nor does a carmaker's literature cover it, so public proof is lacking. The title covers the backlight of a display, today usually LED strings fed by a boost driver. TI's LP8866-Q1 and LP8872-Q1 flag open strings, shorted LEDs and LED shorts to ground and report them to the host; TI adds that quick short-to-ground detection avoids glare that could blind the driver at night. GM's 2011 9-4X logs B1289 when the radio finds the PWM brightness line to the rear-seat screens open or shorted 400 ms after enabling it, and the screens then fall back to a fixed brightness. A dark screen whose picture is still faintly visible in sunlight points here rather than to B0455.
- What you may notice
- Screen dark although content is faintly visible in bright light
- Brightness cannot be adjusted or follows no day/night change
- Uneven, flickering or partly dark backlight
- Likely causes
- LikelyLED string or single LED of the backlight failed
- PossibleBacklight driver or its boost stage defective
- RareBrightness control line open or shorted
- Repair
- Medium · Usually a job for a workshop.Typical cost: €150 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.