High Speed CAN Communication Bus (-) High
2003-2003 Mazda B2300 2.3L I4
The 2003 Mazda B2300 is equipped with a 2.3L inline-4 engine. Below you'll find detailed u0008 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
The CAN Low wire voltage is higher than expected, indicating a short to power.
Symptoms
- CAN bus failure
- Multiple communication errors
- Systems unresponsive
Common Causes
- CAN L shorted to battery voltage
- Wiring harness damage
- Module fault driving CAN L high
Diagnostic Steps
- Measure CAN L voltage
- Disconnect modules to isolate
- Inspect wiring for shorts to power circuits
- Check harness routing near power wires
Repair Notes
Repair CAN L short to power. Ensure CAN wiring is properly separated from power wiring.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
- U0028Vehicle Communication Bus A Performance
U0008 on Other Vehicles
Common Questions
What does code U0008 mean on a 2003-2003 Mazda B2300?
U0008 stands for "High Speed CAN Communication Bus (-) High". The CAN Low wire voltage is higher than expected, indicating a short to power.
What are the symptoms of U0008 on a Mazda B2300?
Common symptoms of U0008 include: CAN bus failure, Multiple communication errors, Systems unresponsive.
What causes U0008 on a 2003-2003 Mazda B2300?
Common causes of U0008 include: CAN L shorted to battery voltage, Wiring harness damage, Module fault driving CAN L high.
Last updated: March 2026