U0053 code meaning
Vehicle Communication Bus C (-) High
What U0053 means
U0053 reports too much voltage on the (-) conductor of Vehicle Communication Bus C, meaning CAN-Low if Bus C is built as a high-speed CAN, and NXP's TJA1041 application note states that a short of CAN-Low either to battery or to the 5 V transceiver supply makes communication impossible, while onsemi's measurements show the transmitting node stuck in endless failed attempts. All Bus C members go quiet together. A fault-tolerant low-speed bus separates the two cases: the TJA1055 data sheet treats CAN-Low at 5 V as a failure it simply tolerates, but at battery voltage it switches off its CAN-Low driver after a delay and receives over CAN-High alone. No manufacturer documents U0053 publicly. With the ignition on, CAN-Low near 5 V or battery voltage against ground confirms the fault.
U0053 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 U0053
- All functions on Bus C drop out at once (high-speed type)
- Lost-communication codes in modules on other networks
- Warning lamps or fallback modes depending on the affected modules
Common causes of U0053
- Most likely(-) wire of Bus C touching a battery or 5 V feed
- PossibleMoisture in a connector bridging the (-) wire to a supply pin
- Less likelyDamaged transceiver holding CAN-Low high
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus c wiringCAN transceiver
What each part of U0053 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 53 | The exact fault in that area. |
What to do next
- Note U0053 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 U0053
What does U0053 mean?
U0053 means "Vehicle Communication Bus C (-) High". U0053 reports too much voltage on the (-) conductor of Vehicle Communication Bus C, meaning CAN-Low if Bus C is built as a high-speed CAN, and NXP's TJA1041 application note states that a short of CAN-Low either to battery or to the 5 V transceiver supply makes communication impossible, while onsemi's measurements show the transmitting node stuck in endless failed attempts. It is a generic code, so it means the same on every make.
Is it safe to drive with U0053?
Drive gently and only to a workshop. With U0053 the car can go into limp mode (reduced power) to protect itself.
Will U0053 fail an emissions test?
U0053 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 U0053 to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will U0053 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.