U0037
Vehicle Communication Bus B
Communication network (CAN bus)
Generic OBD-II
Medium
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.
Medium
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.
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?+
It depends which modules are on bus B. If a powertrain or brake module dropped off, get it towed; if it's body/comfort systems, it's usually drivable but should be fixed.
Can I just clear U0037?+
Only if the fault was a one-time glitch. A real wiring or module problem will set it again quickly.
Related codes
Often seen with U0037
Read & clear U0037 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