What causes a U0242 code?

U0242 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a U0242 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U0242 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

Log in Sign up

OBD-II

U0242

Lost Communication With Headlamp Control Module B

What it means

System cannot reach the right or secondary headlamp control module. Affects modern LED or adaptive lighting systems.

Sign in to view symptoms, probable causes, diagnostic steps, severity, and related codes

Log in Sign up free