U0016 code meaning
Medium Speed CAN Communication Bus (-) Low
What U0016 means
U0016 reports CAN-Low of the medium-speed bus, the (-) wire, sitting below its valid range, typically through a short to ground. Transferred from the high-speed physical layer, which Saab's two-wire terminated mid-speed GMLAN resembles, this is a fault the bus tolerates: onsemi measured continuing transmission with deformed levels, and NXP files it as a hidden failure visible only to transceivers with diagnosis. The comfort network therefore usually keeps working, but becomes more sensitive to interference; drivers rarely notice anything beyond sporadic glitches. No manufacturer documents U0016 publicly. Because the fault hides so well, the code itself is often the only clue; measure CAN-Low against ground with the battery disconnected and follow the harness near sharp edges.
U0016 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0016
- Usually no lasting malfunction, code found during a scan
- Sporadic glitches in comfort functions
Common causes of U0016
- Most likelyMedium-speed CAN-Low chafed against a ground point or sheet edge
- PossibleWater ingress in a footwell or door connector
- Less likelyComfort module transceiver internally shorted on CAN-Low
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
CAN low wireBody control module
What each part of U0016 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 16 | The exact fault in that area. |
What to do next
- Note U0016 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 U0016
What does U0016 mean?
U0016 means "Medium Speed CAN Communication Bus (-) Low". U0016 reports CAN-Low of the medium-speed bus, the (-) wire, sitting below its valid range, typically through a short to ground. It is a generic code, so it means the same on every make.
Is it safe to drive with U0016?
U0016 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0016 fail an emissions test?
U0016 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 U0016 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U0016 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.