What does code U0242 mean?

Q: What does code U0242 mean?

Lost Communication With Headlamp Control Module B. U0242 is a generic communication fault indicating that the vehicle's main control module has lost the CAN (Controller Area Network) data link with the headlamp control module B, which is the second headlamp control module in a multi-module lighting system. The computer detects this when it stops receiving the periodic status messages that module is programmed to broadcast over the network.

DTC codes / U02xx · Lost communication with a control module / U0242

U0242Lost Communication With Headlamp Control Module B

U0242 is a generic communication fault indicating that the vehicle's main control module has lost the CAN (Controller Area Network) data link with the headlamp control module B, which is the second headlamp control module in a multi-module lighting system. The computer detects this when it stops receiving the periodic status messages that module is programmed to broadcast over the network.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaLost communication with a control module

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.