U0024Low Speed CAN Communication Bus (-) Open
- Generic OBD-II code · Network
- How the car detects it
- U0024 reports an interruption of the (-) line, CAN-Low, of a two-wire low-speed CAN. Under the ISO 11898-3 fault-tolerant scheme this wire idles near 5 V and is pulled toward ground for dominant bits. NXP's TJA1055 counts a broken CAN-Low as failure 2, keeps drivers and termination as they are and goes on receiving differentially; it can flag the break only when the gap separates transmitter and receiver, which makes its error output flicker. Because the network keeps running, the fault often surfaces only as a stored code in modules beyond the break. Places where wires flex, such as door or tailgate transitions, are obvious suspects. The single-wire GM low-speed GMLAN has no (-) line, so the code has no meaning there. No manufacturer documents U0024 publicly.
- What you may notice
- Typically no symptom, code found during a scan
- Comfort functions behind the break react sluggishly or sporadically
- Likely causes
- LikelyCAN-Low wire broken in a door or tailgate harness
- PossibleCAN-Low terminal backed out of its connector
- PossibleCorroded CAN-Low contact after water entry
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.