What causes a U0394 code?

U0394 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 U0394 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with U0394 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

U0394

Network/CAN bus communication code U0394

What it means

Software Incompatibility with Roof Control Module. Software mismatch prevents the vehicle from safely operating convertible or sunroof mechanisms.