U0059 code meaning
Vehicle Communication Bus D (+) High
What U0059 means
U0059 means the (+) line of Vehicle Communication Bus D sits at too high a voltage, typically from contact with a battery or 5 V feed. On a high-speed CAN layout the line concerned is CAN-High, and the fault belongs to the shorts NXP calls hidden: communication goes on, and only a transceiver with bus diagnosis can report it. NXP's TJA1041 note mentions a further side effect, namely that the bus wake-up logic of that device was designed so that a CAN-High short to battery does not wake the network while it goes to sleep; a hint that such a short can otherwise interfere with the network going to sleep. Fault-tolerant low-speed hardware like the TJA1055 handles it in two timed steps and ends on CAN-Low alone. No manufacturer documents U0059 publicly. Measured against ground, CAN-High sitting near supply voltage settles the diagnosis.
U0059 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0059
- Usually no symptom, code found during a scan
- Occasional single warning from a module on Bus D
Common causes of U0059
- Most likely(+) wire of Bus D touching a battery or 5 V feed
- PossibleMoisture in a connector bridging the bus wire to supply
- Less likelyAftermarket device tapped into the bus wire
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus d wiringCAN transceiver
What each part of U0059 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 59 | The exact fault in that area. |
What to do next
- Note U0059 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 U0059
What does U0059 mean?
U0059 means "Vehicle Communication Bus D (+) High". U0059 means the (+) line of Vehicle Communication Bus D sits at too high a voltage, typically from contact with a battery or 5 V feed. It is a generic code, so it means the same on every make.
Is it safe to drive with U0059?
U0059 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0059 fail an emissions test?
U0059 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 U0059 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0059 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.