U0181
Lost Communication With Headlamp Leveling Control Module A
Communication network (lighting)
Generic OBD-II
Low
What it means
U0181 means the network has lost communication with the headlamp leveling control module, which automatically adjusts headlight aim for load and road angle. The headlights still work, but without leveling the beams may sit too high or too low. That mainly matters at night, where poor aim can dazzle oncoming traffic or under-light the road, so it's a low-severity but worth-fixing fault.
Low
Can I keep driving? Yes — the headlights still work but may not auto-level. Aim can be off at night, so have it checked, but it's safe for normal driving.
Common symptoms
What you'll notice
- Headlight or lighting warning message on the dash
- Headlamps not auto-leveling; beam aim high, low, or fixed
- Possible glare to oncoming traffic or poorly lit road ahead at night
- Headlamp leveling module unreachable when scanned
Common causes
Most likely first
- Open, shorted, or chafed wiring to the headlamp leveling moduleLikely
- Corroded or loose connector at the moduleCommon
- Blown fuse or lost power/ground to the moduleCommon
- Failed headlamp leveling control module or a faulty leveling sensor on its networkLess often
- Bus fault preventing the module from reportingLess often
How to diagnose & fix
Work through it in order
- Scan all modules and confirm the leveling module is offline.
- Check its power, ground, and fuse feeds.
- Inspect the wiring and connector at the module for damage or corrosion.
- Test the CAN bus lines to the module for open or short.
- If wiring and power are good, replace the module, clear the code, and confirm the headlights level correctly.
FAQ
Quick answers
Is it safe to drive with U0181?+
Yes for normal driving. The main concern is at night — without auto-leveling the beams may sit too high and dazzle oncoming drivers or too low and under-light the road. Have it corrected.
Can I just clear U0181?+
It returns while the module stays offline. The wiring, power, or module fault needs to be repaired to restore leveling.
Related codes
Often seen with U0181
Read & clear U0181 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX