What causes a U0742 code?

U0742 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 U0742 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U0742 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

OBD-II

U0742

Network/CAN bus communication code U0742

What it means

Lost communication with the Active Grille Shutter (AGS) Module. This module controls airflow to the radiator for fuel efficiency and engine cooling.