U0042

Vehicle Communication Bus B (-) Open

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$6–56 (est.)

Symptoms

Check Engine light comes on
Loss of communication between some modules
Incorrect operation of systems using the CAN bus
Errors in other vehicle systems
Possible problems with diagnostics

Causes

CAN B bus wire break (-)
Poor contact in connectors
Short circuit in the circuit
Failure of one of the modules on the bus
Wiring harness damage

How to Fix

Check the integrity of the CAN B bus wires (-)
Inspect connectors for oxidation or damage
Check the resistance in the circuit
Diagnose modules connected to the bus
If necessary, replace damaged wires or connectors

Related codes

U0041 U0043 U0044