OBD2 code U0003: High Speed CAN Communication Bus (+) Open
The CAN-High line of the high-speed bus is open.
Detected Root Component
Network Component
Observed Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Possible Causes
- CAN-High wire broken or pin pushed back
- Corroded module connector
- Harness damage after repair or accident
Tools Required
Interactive Diagnostic
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Parts likely to be the cause (Moteur (général))
Moteur (général)
Photo d'illustration : Moteur (général)
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Frequently asked questions about code U0003
What does code U0003 mean? ▾
OBD2 code U0003: High Speed CAN Communication Bus (+) Open. The CAN-High line of the high-speed bus is open.
What are the symptoms of code U0003? ▾
Code U0003 may cause: Multiple warning lights may illuminate, Affected modules may go into limp mode or shut down, Specific functions inoperative depending on module, Diagnostic tools may show communication faults. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code U0003? ▾
The most common causes of code U0003 are: CAN-High wire broken or pin pushed back, Corroded module connector, Harness damage after repair or accident. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code U0003? ▾
Yes, code U0003 is critical (Critical). Avoid driving and consult a professional promptly to prevent major damage.
How do I fix code U0003? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: CAN-High wire broken or pin pushed back, Corroded module connector, Harness damage after repair or accident. Difficulty: Medium · Estimated time: 30-60min.