U0049
Vehicle Communication Bus C (+) Low
U0049 is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus C (+) Low. Common causes: broken or damaged wires in the communication bus circuit, short circuit in positive circuit. Estimated repair cost: $6–56.
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
Error U0049 by Vehicle Brand
FAQ
What does the U0049 code mean?
U0049 is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus C (+) Low
What causes a U0049 error code?
The most common causes of U0049 include: 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.
How do I fix a U0049 diagnostic trouble code?
To fix U0049: 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. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U0049?
Do not drive — repair immediately
How much does it cost to fix U0049?
The estimated repair cost for U0049 is $6–56. Actual cost depends on your vehicle, location, and labor rates.
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