U0048
Vehicle Communication Bus C (+) Open
Vehicle communication network
Generic OBD-II
Medium
What it means
U0048 means the positive wire of the vehicle's Bus C communication network is open — an electrical break in the circuit. Modules that rely on Bus C can no longer send or receive data, so they drop offline and trigger warning lights. It is a physical wiring fault, typically a broken wire, a disconnected connector, or a corroded terminal.
Medium
Can I keep driving? Often driveable, but with an open bus wire the modules on Bus C can go silent, bringing warning lights and dead features, and limp mode if a powertrain module is involved — diagnose promptly.
Common symptoms
What you'll notice
- One or more modules on Bus C completely unresponsive
- Multiple warning lights on together
- Features tied to this bus not working
- Communication errors reported when scanned
Common causes
Most likely first
- Broken or open Bus C positive (+) wireLikely
- Disconnected or corroded connector on the busCommon
- Broken pin or terminal at a moduleCommon
- Wiring damaged after service or a collisionLess often
How to diagnose & fix
Work through it in order
- Scan all modules and note which ones on Bus C are missing.
- Inspect the Bus C (+) wiring for breaks, and check connectors for backed-out or corroded terminals.
- Perform a continuity test along the bus wire to locate the open.
- Check the connectors at each module sharing the bus.
- Repair the broken wire or terminal, clear codes, and retest.
FAQ
Quick answers
Is it safe to drive with U0048?+
An open bus wire silences the modules on Bus C. Whether that matters for driving depends on the manufacturer's bus layout — comfort systems are a nuisance, but a powertrain or brake module going quiet can mean limp mode, so get it checked.
Can I just clear U0048?+
No — an open circuit is a physical break in the wire and the code returns immediately. The wiring has to be repaired.
Related codes
Often seen with U0048
Read & clear U0048 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX