U0074

Control Module Communication Bus B Off

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$6–56 (est.)

Symptoms

Some comfort systems do not work (climate control, audio system)
Check Engine light comes on
Errors in other systems
Problems with central locking
Dashboard malfunctions

Causes

Broken or damaged CAN B bus wires
Short circuit in CAN bus
Fault in one of the modules connected to the bus
Problems with module power supply
Corrosion of connectors

How to Fix

Check the integrity of the CAN B bus wiring
Check connectors and contacts for corrosion
Check the power supply of the modules connected to the bus
Disable the modules one by one to find the faulty one.
Check CAN bus resistance

Related codes

U0073 U0100 U0121