High Speed CAN Communication Bus (+) Low
2004-2004 Ferrari 360 Modena 3.6L V8
The 2004 Ferrari 360 Modena is equipped with a 3.6L V8 engine. Below you'll find detailed u0004 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
The CAN High wire voltage is lower than expected, indicating a short to ground or excessive load on the bus.
Symptoms
- Communication failures
- Multiple DTCs from various modules
- Intermittent system operation
Common Causes
- CAN H wire shorted to ground
- Module pulling CAN H low
- Damaged wiring insulation
- Water intrusion in connector
Diagnostic Steps
- Measure CAN H voltage
- Disconnect modules one at a time to find short source
- Inspect wiring for chafing against ground
- Check connectors for moisture
Repair Notes
Find and repair the short to ground on the CAN H wire. Inspect for damaged insulation.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
- U0028Vehicle Communication Bus A Performance
U0004 on Other Vehicles
Ferrari 296 GTB
2022-2022 3.0L V6 Hybrid
Ferrari 296 GTB
2023-2023 3.0L V6 Hybrid
Ferrari 296 GTB
2024-2024 3.0L V6 Hybrid
Ferrari 296 GTS
2022-2022 3.0L V6 Hybrid
Ferrari 296 GTS
2023-2023 3.0L V6 Hybrid
Ferrari 296 GTS
2024-2024 3.0L V6 Hybrid
Ferrari 360 Challenge Stradale
2003-2003 3.6L V8
Ferrari 360 Challenge Stradale
2005-2005 3.6L V8
Common Questions
What does code U0004 mean on a 2004-2004 Ferrari 360 Modena?
U0004 stands for "High Speed CAN Communication Bus (+) Low". The CAN High wire voltage is lower than expected, indicating a short to ground or excessive load on the bus.
What are the symptoms of U0004 on a Ferrari 360 Modena?
Common symptoms of U0004 include: Communication failures, Multiple DTCs from various modules, Intermittent system operation.
What causes U0004 on a 2004-2004 Ferrari 360 Modena?
Common causes of U0004 include: CAN H wire shorted to ground, Module pulling CAN H low, Damaged wiring insulation, Water intrusion in connector.
Last updated: March 2026