U0181 Code: Meaning, Causes, and Symptoms | OBD2 Codes

U0181 – Lost Communication With Dynamic Headlamp Leveling Control Module


U0181 Possible Symptoms


Engine Light ON (or Service Engine Soon Warning Light)


U0181 Possible Causes


Faulty Dynamic Headlamp Leveling (DHL) Control Module,DHL Control Module harness is open or shorted,DHL Control Module circuit poor electrical connection


U0181 Description


Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module.