Home >> Land Rover >> 2021 >> Range Rover Base >> Repair and Diagnosis >> Quick Lookups >> Common Specs & Procedures >> Diagnostic Trouble Code Index DTC: Headlight Control Module (HCM) -- Range Rover/L405 >> General Information >> Description And Operation >> Diagnostic Trouble Code Index - DTC: Headlamp Control Module (HCM) (G2167619) >> DTC U0542-81: Invalid Data Received From Headlamp Control Module "A" - Invalid serial data received >> Possible Causes