What causes a U3342 code?

U3342 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 U3342 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U3342 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

U3342

Manufacturer-specific network code U3342

What it means

Communication fault within the emissions control network. The SCR or DEF controllers are not responding to the main Engine Module.

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

Log in Sign up free