U0046

Vehicle Communication Bus C

Q: Is it safe to drive with U0046?

Often yes for short trips, but because a bus fault can disable systems you rely on, have it diagnosed before extended driving.

Q: Can I just clear U0046?

You can, but it returns unless the underlying wiring fault or failing module is repaired. Check the battery first, as low voltage can trigger it.

Communication network (CAN bus) Generic OBD-II Medium

What it means

U0046 is a general fault on vehicle communication Bus C, meaning a module detected a problem with this data bus that lets control modules share information. It usually surfaces as warning lights and modules that won't respond to a scan tool. Which features are affected depends on what "Bus C" carries on your specific vehicle.

Medium

Can I keep driving? Usually drivable, but a bus fault can drop several modules offline at once — expect warning lights and reduced features until it's diagnosed.

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

One or more warning lights on across different systems
Modules on Bus C stop responding to a scan tool
Intermittent electrical features dropping out and returning
Loss of specific functions carried on this bus

Common causes

Most likely first

Open, short, or high resistance in the Bus C wiring or connectorsLikely
Chafed, pinched, or corroded bus wiringCommon
A failing module disrupting the busCommon
Water intrusion or corrosion at a connector or spliceLess often
Weak battery or low system voltage setting spurious network codesLess often

How to diagnose & fix

Work through it in order

Scan every module and note which are unreachable to locate the fault on Bus C.
Check battery voltage and charging; correct low voltage, then clear and re-test.
Inspect Bus C wiring and connectors for damage, corrosion, or water intrusion.
Measure bus voltages and resistance to find an open, short, or bad termination.
Isolate modules one at a time to find a unit disrupting the bus; repair the wiring or replace the confirmed faulty module.

FAQ

Quick answers

Is it safe to drive with U0046?+

Often yes for short trips, but because a bus fault can disable systems you rely on, have it diagnosed before extended driving.

Can I just clear U0046?+

You can, but it returns unless the underlying wiring fault or failing module is repaired. Check the battery first, as low voltage can trigger it.

Read & clear U0046 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