U024A code meaning
Lost Communication With Interior Lighting Control Module A
What U024A means
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 color 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.
U024A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U024A
- Interior lights do not come on or stay on
- Ambient lighting color or brightness cannot be changed
Common causes of U024A
- Most 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
- Less likelyLighting module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Interior lighting module aCAN bus
What each part of U024A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4A | The exact fault in that area. |
What to do next
- Note U024A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U024A
What does U024A mean?
U024A means "Lost Communication With Interior Lighting Control Module A". Interior lighting control module A switches and dims cabin lights such as dome, footwell and ambient strips. It is a generic code, so it means the same on every make.
Is it safe to drive with U024A?
U024A does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U024A fail an emissions test?
U024A is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U024A to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U024A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.