U009EVehicle Communication Bus J Performance
- Generic OBD-II code · Network
- How the car detects it
- U009E flags unreliable traffic on Vehicle Communication Bus J without a total loss. No manufacturer publishes a use of U009E. Interference is a likely source. Texas Instruments names fluorescent lamps, switching power supplies and motor drives as typical emitters of common-mode noise that couples onto bus lines, and explains that a receiver without good rejection may take it for data. A twisted pair and differential signalling keep this in check, so opened twists or retrofitted electronics near the harness are suspects. NXP adds that tolerated wiring faults also worsen electromagnetic behaviour. Where messages go unacknowledged, Wikipedia notes that nodes often resend them repeatedly, which can drive them into the error-passive state.
- What you may notice
- Short dropouts on Bus J, often with certain loads switched on
- Warnings that appear briefly and clear
- Likely causes
- LikelyInterference from nearby loads or retrofitted electronics
- PossibleBus wires untwisted at a repair
- PossibleLoose contact in a Bus J connector
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.