Network, generic

U0542 Invalid Data Received From Headlamp Control Module A

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Headlamp control modules run adaptive lighting such as swivelling, levelling, matrix segments and LED daytime lights, frequently with one module per headlamp. U0542 means a receiver, for example the body or lighting master module, gets messages from module A that fail its checks. No manufacturer publishes text for U0542. Jaguar documents the units by letter: on the 2020 XE, headlamp control modules A and B stored false low-voltage faults for position and daytime lights because current and board voltage were sampled out of phase (SSM74402), and new software with a revised threshold was announced. Bentley's Continental GT treats the left and right light controllers as separate addresses for reprogramming. Expect a headlamp warning and adaptive features held in a default position. U0241 is lost communication.

Likely causes

Headlamp module A software (reprogramming released)
Headlamp or module replaced without coding/configuration
Moisture or corrosion at the headlamp connector

Symptoms

  • Check headlamp or lighting system warning
  • Adaptive or cornering light not working on one side
  • Daytime running light or position light affected

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–900
Time0.3–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

headlamp module a

Related codes

U0241U0543U0242

References: static.nhtsa.gov, static.nhtsa.gov, en.wikipedia.org.