U0014
Medium Speed CAN Communication Bus (+) High
Communication / CAN bus
Generic OBD-II
Medium
What it means
U0014 is set when the voltage on the medium-speed CAN bus (+) line reads higher than expected. The medium-speed bus links body, cluster, and comfort modules rather than the engine, so the car usually still runs — but affected modules can drop offline, triggering warning lights and disabling features that share this bus.
Medium
Can I keep driving? Usually yes — the medium-speed bus carries body and comfort modules, not the engine — but if it disables your gauges or lighting, treat that as a safety issue and fix it soon.
Common symptoms
What you'll notice
- Multiple warning lights or messages on the dash
- Gauges, lighting, or comfort features on the bus acting up or dead
- One or more modules show no communication to a scan tool
- Intermittent electrical glitches that come and go
Common causes
Most likely first
- Chafed or damaged medium-speed CAN wiring shorted to a voltage sourceLikely
- Corroded or loose connector at a module on the busCommon
- A failed module pulling the bus (+) line highCommon
- Water intrusion into a connector or harnessLess often
- Incorrect or missing bus terminating resistanceLess often
How to diagnose & fix
Work through it in order
- Scan every module and record all stored U-codes to see which are offline.
- Inspect the medium-speed CAN wiring and connectors for chafing, corrosion, or a short to power.
- Wiggle-test connectors while watching live data to catch an intermittent fault.
- Disconnect modules one at a time to find one dragging the bus (+) line high.
- Repair the wiring or connector, or replace the confirmed faulty module, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with U0014?+
Often yes, since the medium-speed bus doesn't run the engine. But if it disables your speedometer, gauges, or lighting, treat those as safety issues and repair it promptly.
Can I just clear U0014?+
It'll clear, but it returns as soon as the bus sees the same high voltage again. Repair the wiring or module first.
Related codes
Often seen with U0014
Read & clear U0014 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