U0087 code meaning
Vehicle Communication Bus F (-) High
What U0087 means
U0087 stands for a (-) wire on Vehicle Communication Bus F pulled too high, most often through contact with battery voltage. If Bus F is the FlexRay of an Audi A6/A7, the wire is bus minus (BM); held above BP, it creates a constant negative difference that receivers treat as DATA_0, so the channel looks permanently busy and no node can place a frame. NXP's TJA1081B tolerates such a short on its bus pins without damage. On a CAN, CAN-Low at supply voltage cannot be pulled down for a dominant bit; onsemi and NXP both describe the bus as blocked. Volvo includes a short of CAN-Low to power among the causes of its truck code U008088. No manufacturer documents U0087 itself. With ignition on, a (-) wire near battery voltage confirms the fault.
U0087 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0087
- All functions on Bus F fail together
- Warning lamps and messages from several systems
Common causes of U0087
- Most likely(-) wire of Bus F shorted to a battery or ignition feed
- PossibleMoisture in a connector linking the (-) pin to a supply
- Less likelyInternally shorted transceiver in one module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus f wiringCAN transceiver
What each part of U0087 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 87 | The exact fault in that area. |
What to do next
- Note U0087 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 U0087
What does U0087 mean?
U0087 means "Vehicle Communication Bus F (-) High". U0087 stands for a (-) wire on Vehicle Communication Bus F pulled too high, most often through contact with battery voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with U0087?
Drive gently and only to a workshop. With U0087 the car can go into limp mode (reduced power) to protect itself.
Will U0087 fail an emissions test?
U0087 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 U0087 to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will U0087 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.