What does it mean?
U1139 is a Network (CAN bus, module communications) fault code. It indicates: DIS AMP Unit Fan Operation Error - no plug put or line open(Fan is not running although it should be on) .
Symptoms
- No fan noise at all from the unit, even when the audio system is working hard
- The unit overheating, cutting the volume, distorting or shutting down after a period of use
- Screen blanking, freezing or restarting, particularly in hot weather
- Audio dropping out on long journeys and returning after the vehicle cools down
- Burnt smell from behind the trim in severe cases
- The code returns as soon as the system tries to run the fan
Likely causes
- Fan connector unplugged or not latched, often after audio work or trim removal
- Open circuit in the fan supply or control wire, or a broken pin in the connector
- Seized or worn fan motor that no longer turns
- Blown fuse feeding the unit or the fan circuit
- Failed output driver inside the display and amplifier unit
- Corrosion or moisture in the fan connector
- Dust and debris jamming the fan blade
How to fix it
- Remove the trim and confirm the fan connector is fully seated and undamaged
- Try to spin the fan by hand to see whether it is seized or obstructed by dust
- Check the fuse feeding the unit and measure supply voltage at the fan connector while the fan is commanded on
- Apply a controlled supply directly to the fan to confirm whether the motor still runs
- Test the fan control and supply wires for open circuit and high resistance back to the unit
- Inspect the connector for corrosion, spread terminals and moisture, and repair as needed
- Replace the fan if it is dead; replace the display and amplifier unit only if the wiring and fan are good and the output stays inactive