U0037 code meaning
Vehicle Communication Bus B
What U0037 means
U0037 is the umbrella code for Vehicle Communication Bus B, the second neutral network slot after Bus A; each maker decides which network sits behind it, and published uses differ widely. Volkswagen's 2014 Touareg data book sets it when a CAN frame sent on Bus B goes unacknowledged. FCA calls U0037-00 the LIN bus on the 2018-22 Jeep Wrangler, where it came with U0121 and an intermittent ABS lamp caused by a loose ground point G907A. Volvo's brake control module 2 stores U003700 alongside ECM code P25A268 and a lit check-engine lamp on 2017-24 models; software 3.0.3 cures it. On GM's 2026 full-size SUVs and Silverado/Sierra EV the brake module's U0037-88 procedure is swapped with U0028-88, and Ford reflashes the Mustang GTD dynamics module over false U0037 entries.
U0037 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0037
- Warning lamps of the systems on Bus B, e.g. ABS lamp (Jeep) or check-engine lamp (Volvo)
- Stop/start or chassis functions unavailable
- Lost-communication codes stored alongside
Common causes of U0037
- Most likelyLoose or corroded ground or supply of a module on Bus B (FCA: ground G907A)
- Most likelyModule software misreporting or mishandling the bus (Volvo BCM2, Ford VDM, GM brake module 2026)
- PossibleDamaged bus wiring or a poorly seated connector
- Less likelyA module on Bus B that has stopped answering
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus b wiringBus b nodes
What each part of U0037 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 37 | The exact fault in that area. |
What to do next
- Note U0037 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0037
What does U0037 mean?
U0037 means "Vehicle Communication Bus B". U0037 is the umbrella code for Vehicle Communication Bus B, the second neutral network slot after Bus A; each maker decides which network sits behind it, and published uses differ widely. It is a generic code, so it means the same on every make.
Is it safe to drive with U0037?
Drive gently and only to a workshop. With U0037 the car can go into limp mode (reduced power) to protect itself.
Will U0037 fail an emissions test?
U0037 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0037 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0037 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.