U0005High Speed CAN Communication Bus (+) High
- Generic OBD-II code · Network
- How the car detects it
- U0005 flags CAN-High, the (+) wire of the high-speed bus, sitting above its permitted range, generally because it touches battery voltage or a 5 V feed. Unlike a ground short this does not have to halt traffic: onsemi and NXP both found that frames still pass, but the voltage picture is distorted, noise immunity worsens and, on networks with a large capacitive load, bit timing can be violated. NXP therefore classes it as a hidden bus failure that only transceivers with diagnosis can see. The usual result is occasional message loss, intermittent warnings, or a single module that reports the fault while the car drives normally. No manufacturer documents U0005 publicly. Measuring CAN-High against ground with ignition on shows a value near supply voltage instead of about 2.5 to 3.5 V.
- What you may notice
- Sporadic warnings, often with no lasting malfunction
- Individual messages or modules dropping out under load or in damp weather
- Likely causes
- LikelyCAN-High chafed through against a battery or ignition feed
- PossibleMoisture bridging CAN-High to a supply pin in a connector
- RareIncorrectly connected accessory or retrofit module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.