U0002
High Speed CAN Communication Bus Performance
The high-speed CAN bus is functional but performance is degraded — frame errors, bit errors or excessive bus load have been detected. Communication may be intermittent rather than completely lost, leading to sporadic warning lamps.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Corrosion or poor contact in CAN connectorsCommon
- Electromagnetic interference (aftermarket electronics)Possible
- One module sending malformed framesPossible
Parts involved
- CAN Bus Wiring
- Control Module
U0002 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.