Vehicle Communication Bus B
What it means
U0037 is a general communication fault on the vehicle's bus B network — modules on that bus aren't exchanging data as expected. What you notice depends on which systems the manufacturer assigned to bus B, so it ranges from a few warning lights to features dropping out. Scanning all modules to see which ones went quiet is the key first step.
Can I keep driving? Depends on what rides on bus B — often drivable with warning lights, but confirm no powertrain or safety module dropped off first.
Real-world scan data
Appears alongside · share of U0037 scans
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 dash warning lights
- Modules on bus B unresponsive or intermittent when scanned
- Features tied to that bus behave erratically or stop working
- Additional U-series codes stored alongside this one
Common causes
Most likely first
- Open, shorted, or chafed wiring on the bus B networkLikely
- Corroded or loose connector pins on the busCommon
- Water intrusion into a bus connector or moduleCommon
- A failed module disrupting communication on bus BLess often
- Wiring damage from a prior repair or rodentsLess often
How to diagnose & fix
Work through it in order
- Scan all modules and list which ones on bus B stopped responding.
- Check the manufacturer's wiring diagram to see which systems bus B serves.
- Inspect the bus B harness and connectors for damage, corrosion, or moisture.
- Disconnect suspect modules one at a time to find one loading down the bus.
- Repair the fault, clear the code, and confirm every module reports back.
FAQ
Quick answers
Is it safe to drive with U0037?+
Can I just clear U0037?+
Related codes
Read & clear U0037 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.