U0181Lost Communication With Headlamp Leveling Control Module
- Generic OBD-II code · Network
- How the car detects it
- U0181 says the module that controls automatic headlamp levelling has dropped off the bus. That module reads ride-height sensors on the axles and drives the actuator motors in the headlamps to keep the beam at the right angle under load. GM uses the code: the Saab 9-5 (2010-2011) U-code list names it Lost Communication With Headlamp Leveling Control Module, and a GM bulletin for the 2017-2021 GMC Acadia and Cadillac XT5 lists U0181 among the U-codes caused by a chafed dash harness or water in the BCM. Per GM it sets when the module's supervised periodic message is missing at 9-16 V. U0180 is the automatic lighting module, U0182 and U0183 the front and rear lighting modules. No MIL; beam height may stay fixed.
- What you may notice
- Headlamp beam height no longer adjusts
- Headlamp or lighting warning in the cluster
- Oncoming traffic dazzled or road poorly lit when loaded
- Likely causes
- LikelyLevelling module without power or ground
- PossibleChafed harness or water in connectors or BCM area (GM Acadia/XT5)
- PossibleCorroded connector at the module near the headlamp
- RareHeadlamp levelling module faulty or not coded
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.