U0057: Vehicle Bus D Open Circuit
The U0057 code indicates that a control module has detected an open circuit in the vehicle's Communication Bus 'D'. This means data signals cannot be transmitted over that specific bus, preventing communication between modules connected to that network (typically a low- or high-speed CAN bus designated as Bus D by the manufacturer).
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Open circuit in the Bus D wiring (CAN High or CAN Low)
- Damaged, loose, or corroded connector pins at a module on Bus D
- Faulty or missing termination resistor on Bus D
- Internal failure of the CAN transceiver in a module connected to Bus D
- Short to voltage or ground on Bus D lines causing the bus to go recessive (simulating an open)
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Loss of communication with modules on Bus D (e.g., ABS, airbag, or instrument cluster)
- Erratic behavior or non-functioning of systems tied to Bus D
4. Step-by-Step Diagnosis
Scan all modules for communication faults and verify which modules are offline on Bus D.
Inspect Bus D wiring and connectors for damage, corrosion, or loose pins.
Measure resistance between CAN High and CAN Low at the bus termination points (should be ~60 ohms with two termination resistors).
Check for shorts to power or ground on the CAN lines using a multimeter.
If wiring is intact, isolate modules one by one to identify a faulty transceiver or internal module failure.
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but systems relying on Bus D communication (such as stability control or airbags) may not function properly. It is recommended to diagnose and repair the issue promptly to avoid safety risks.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. Simple wiring repairs can cost $100-$300, while replacing a faulty module may range from $400 to $1,200 including labor.