U0015 code meaning
Medium Speed CAN Communication Bus (-) Open
What U0015 means
U0015 stands for a break in CAN-Low, the (-) conductor of the medium-speed CAN. Modules separated by the break stop exchanging data with the rest of the network, whereas units still connected on both wires keep working; which functions disappear therefore depends on where the line is cut. Ford's F-Super Duty bulletin shows how a single open connector in the MS-CAN switches off the HVAC controls, the front switch panel and the headlamp function together. Common high-speed transceivers cannot diagnose a line interruption themselves (NXP), so the code results from the module's own reasoning about missing replies. No manufacturer documents U0015 publicly. Wiring that moves, such as door, tailgate and seat harnesses, and connectors opened during body or upfit work are the first places to check.
U0015 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0015
- Only some comfort functions lost, depending on break location
- Fault varies when doors or seats are moved
Common causes of U0015
- Most likelyCAN-Low conductor fractured in a moving harness section
- PossibleConnector not reconnected after body or upfit work
- Less likelyCorroded CAN-Low splice
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
CAN low wireModule connector
What each part of U0015 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 15 | The exact fault in that area. |
What to do next
- Note U0015 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 U0015
What does U0015 mean?
U0015 means "Medium Speed CAN Communication Bus (-) Open". U0015 stands for a break in CAN-Low, the (-) conductor of the medium-speed CAN. It is a generic code, so it means the same on every make.
Is it safe to drive with U0015?
U0015 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0015 fail an emissions test?
U0015 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 U0015 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U0015 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.