U024ALost Communication With Interior Lighting Control Module A
- Generic OBD-II code · Network
- How the car detects it
- Interior lighting control module A switches and dims cabin lights such as dome, footwell and ambient strips. In newer cars these are often small LIN nodes under a master, usually the body controller. A Microchip demo board for LIN ambient light illustrates the traffic: the master sends colour and brightness per zone and polls a status frame back. GM's Saab 9-5 documentation states that on a LIN subsystem the primary module records a lost-contact code for any node that stops answering, and that is the route by which U024A is normally stored. No manufacturer documents U024A publicly, so timeouts are unknown. Typical findings are a loose plug at a roof or door light unit or a LIN line chafed in the headliner. Cabin lights stay dark or on, and ambient colours freeze. Module B is U02BF; corrupt data from A give U054B.
- What you may notice
- Interior lights do not come on or stay on
- Ambient lighting colour or brightness cannot be changed
- Likely causes
- LikelyLoose or corroded plug at a roof, door or footwell light unit
- PossibleLIN line chafed or pinched in headliner, door or trim
- PossibleLighting module without power or ground
- RareLighting module internally faulty
- Repair
- Easy · Often possible to do yourself.Typical cost: €0 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.