U0033
Vehicle Communication Bus A (-) Open
U0033 is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus A (-) Open. Common causes: can a bus wire break (-), short circuit in can line. Estimated repair cost: $6–56.
Symptoms
- Check Engine Light Is On
- Disabling some car systems (ABS, ESP, airbags)
- Problems starting the engine
- Incorrect operation of the dashboard
- Communication errors in other modules
Causes
- CAN A bus wire break (-)
- Short circuit in CAN line
- Oxidation of contacts in connectors
- Malfunction of one of the network modules
- Mechanical damage to the wiring harness
How to Fix
- Visually inspect the wiring harness for damage
- Checking the integrity of the CAN A (-) line with a multimeter
- Cleaning contacts in CAN bus connectors
- Checking line resistance
- Replacing a damaged section of wiring
Related codes
Error U0033 by Vehicle Brand
FAQ
What does the U0033 code mean?
U0033 is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus A (-) Open
What causes a U0033 error code?
The most common causes of U0033 include: CAN A bus wire break (-); Short circuit in CAN line; Oxidation of contacts in connectors; Malfunction of one of the network modules.
How do I fix a U0033 diagnostic trouble code?
To fix U0033: Visually inspect the wiring harness for damage. Checking the integrity of the CAN A (-) line with a multimeter. Cleaning contacts in CAN bus connectors. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U0033?
Do not drive — repair immediately
How much does it cost to fix U0033?
The estimated repair cost for U0033 is $6–56. Actual cost depends on your vehicle, location, and labor rates.
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