U0024

Low Speed CAN Communication Bus (-) Open

Q: 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.

Q: 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.

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.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear U0024 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX