U0042
Vehicle Communication Bus B (-) Open
U0042 is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus B (-) Open. Common causes: can b bus wire break (-), poor contact in connectors. Estimated repair cost: $6–56.
Symptoms
- Check Engine light comes on
- Loss of communication between some modules
- Incorrect operation of systems using the CAN bus
- Errors in other vehicle systems
- Possible problems with diagnostics
Causes
- CAN B bus wire break (-)
- Poor contact in connectors
- Short circuit in the circuit
- Failure of one of the modules on the bus
- Wiring harness damage
How to Fix
- Check the integrity of the CAN B bus wires (-)
- Inspect connectors for oxidation or damage
- Check the resistance in the circuit
- Diagnose modules connected to the bus
- If necessary, replace damaged wires or connectors
Related codes
Error U0042 by Vehicle Brand
FAQ
What does the U0042 code mean?
U0042 is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus B (-) Open
What causes a U0042 error code?
The most common causes of U0042 include: CAN B bus wire break (-); Poor contact in connectors; Short circuit in the circuit; Failure of one of the modules on the bus.
How do I fix a U0042 diagnostic trouble code?
To fix U0042: Check the integrity of the CAN B bus wires (-). Inspect connectors for oxidation or damage. Check the resistance in the circuit. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U0042?
Yes, but get it checked soon
How much does it cost to fix U0042?
The estimated repair cost for U0042 is $6–56. Actual cost depends on your vehicle, location, and labor rates.
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