U0049

Vehicle Communication Bus C (+) Low

Severity

🔴 High

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$6–56 (est.)

Symptoms

Unstable operation of the dashboard
Malfunctions of the car's electronic systems
Other communication errors appear
Problems starting the engine
Incorrect sensor readings

Causes

Broken or damaged wires in the communication bus circuit
Short circuit in positive circuit
Fault in one of the modules connected to the bus
Poor contact in connectors
Corrosion or oxidation of contacts

How to Fix

Check the integrity of the wires in the communication bus circuit
Inspect connectors for oxidation or damage
Check the voltage in the positive circuit of the communication bus
Disable the modules one by one to identify the faulty one.
Check the insulation resistance of the wires

Related codes

U0048 U0050 U0051