U0044

Vehicle Communication Bus B (-) High

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–56 (est.)

Symptoms

Check Engine light comes on
Unstable operation of the vehicle's electronic systems
Lost connection with some modules
Problems with diagnostics via OBD-II connector
Incorrect dashboard readings

Causes

Open or short circuit in CAN B circuit
Poor contact in CAN bus connectors
Wiring harness damage
Fault in one of the modules connected to the bus
Problems with power supply to CAN modules

How to Fix

Check the integrity of the CAN B bus wiring
Inspect and clean the contacts in the connectors
Check voltage on CAN B bus
Diagnose modules connected to the bus
Replace damaged wires or connectors

Related codes

U0041 U0042 U0043