What does code U0004 mean?

High Speed CAN Communication Bus (+) Low: The CAN bus high wire has low voltage.

U0004 is rated as high severity. Address soon — may cause further damage.

U0004

High Speed CAN Communication Bus (+) Low

Network Code · High

What does U0004 mean?

The CAN bus high wire has low voltage.

System: CAN Bus

U0004 is a network diagnostic trouble code indicating high speed can communication bus (+) low. This code is classified as high severity, which means: address soon — may cause further damage.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your vehicle.