U0181 GMC Lost Communication With Dynamic Headlamp Leveling Control Module
Possible causes
– Faulty Dynamic Headlamp Leveling (DHL) Control Module
– DHL Control Module harness is open or shorted
– DHL Control Module circuit poor electrical connection
– DHL Control Module harness is open or shorted
– DHL Control Module circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
U0181 GMC 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.
GMC Vehicle:GMC Acadia,GMC Canyon,GMC Envoy,GMC Savana 1500,GMC Savana 2500,GMC Savana 3500,GMC Sierra 1500,GMC Sierra 2500 HD,GMC Sierra 3500 HD,GMC Terrain,GMC Yukon,GMC Yukon XL 1500,GMC Yukon XL 2500,