U0091Vehicle Communication Bus G (-) Shorted to Bus G (+)
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U0091 closes the Bus G block: the (-) and (+) wires of Vehicle Communication Bus G are joined, on a CAN CAN-Low to CAN-High. No manufacturer has published a use of U0091. With both wires bridged no voltage difference can form, so a high-speed CAN carries no frames at all. Transceiver self-diagnosis is of little help here; NXP notes that its TJA1043 reports shorts to ground and supply but not a short between the two bus wires, so the module concludes the fault from the silence. Measuring is quick: Nissan gives about 60 ohms between the wires as normal and lists zero ohms for a short between them. To find the spot, unplug modules and harness sections one at a time until the reading returns to normal.
- What you may notice
- Complete loss of the functions served by Bus G
- Scan tool cannot reach any module on Bus G
- Likely causes
- LikelyBus wires crushed together, e.g. under a seat rail or panel
- PossibleCorroded or wet splice bridging both wires
- RareInternal short in one module's transceiver
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.