U0041 code meaning
Vehicle Communication Bus B (+) High
What U0041 means
U0041 means the (+) wire of Vehicle Communication Bus B sits at too high a voltage, typically because it touches a battery or 5 V supply. For a high-speed-type CAN this is CAN-High, and NXP classes a short of CAN-High to battery or to VCC as a hidden failure: frames keep flowing, so only a transceiver with bus diagnosis, such as the TJA1043, reports it. On a fault-tolerant low-speed CAN NXP's TJA1055 reacts in two steps after time-outs and finally switches off its CANH driver, running on CAN-Low alone. Either way the vehicle often behaves normally, and the code may sit in memory long before anything fails. No manufacturer documents U0041 publicly. A reading near supply voltage on CAN-High against ground confirms it; check for chafing against feed wires and moisture in connectors.
U0041 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0041
- Often no noticeable symptom, code found during a scan
- Sporadic warnings from one module
Common causes of U0041
- Most likely(+) wire chafed against a battery or 5 V feed
- PossibleMoisture in a connector bridging the (+) wire to a supply pin
- Less likelyFaulty transceiver driving the (+) line high
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 transceiver
What each part of U0041 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 41 | The exact fault in that area. |
What to do next
- Note U0041 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 U0041
What does U0041 mean?
U0041 means "Vehicle Communication Bus B (+) High". U0041 means the (+) wire of Vehicle Communication Bus B sits at too high a voltage, typically because it touches a battery or 5 V supply. It is a generic code, so it means the same on every make.
Is it safe to drive with U0041?
U0041 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0041 fail an emissions test?
U0041 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 U0041 to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will U0041 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.