U0024
Low Speed CAN Communication Bus (-) Open
Communication / CAN bus
Generic OBD-II
Medium
What it means
U0024 sets when the low-speed CAN bus (-) line is open (broken) so modules on that bus can't talk to each other. The low-speed bus typically handles body, comfort, and convenience features rather than the powertrain, so the engine usually runs — but the affected modules go offline and their features stop working until the break is repaired.
Medium
Can I keep driving? Usually driveable — the low-speed bus carries body and comfort modules, not the engine — but expect warning lights and inoperative features until it's fixed.
Common symptoms
What you'll notice
- Warning lights or messages for body and comfort systems
- Features on the low-speed bus (locks, lighting, HVAC, etc.) inoperative
- Modules unreachable by a scan tool
- Intermittent or dead accessory operation
Common causes
Most likely first
- Broken or disconnected low-speed CAN (-) wire (open circuit)Likely
- Corroded, backed-out, or unplugged connector pinCommon
- Harness damage from rodents, chafing, or a prior repairCommon
- A failed module leaving the bus openLess often
- Water and corrosion in a bus spliceLess often
How to diagnose & fix
Work through it in order
- Scan all modules and note which report no communication to narrow down the open's location.
- Inspect the low-speed CAN (-) wiring and connectors between the offline modules for breaks or corrosion.
- Check continuity of the bus (-) line end to end with a meter.
- Repair the broken wire, pin, or splice you find.
- Clear the code and confirm all modules report back online.
FAQ
Quick answers
Is it safe to drive with U0024?+
Usually — the low-speed bus doesn't control the engine. But fix it soon, since it can disable lights, locks, and other convenience and safety features.
Can I just clear U0024?+
You can, but an open circuit won't repair itself; the code returns until the broken wire or connection is fixed.
Related codes
Often seen with U0024
Read & clear U0024 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