Lost Communication - General Bus Timeout
2021-2024 Dacia Spring Electric 🇩🇪
Description
General timeout on the communication bus. Multiple modules are not responding within expected time.
Symptoms
- Multiple systems intermittently offline
- General communication degradation
- Multiple timeout DTCs stored
- Scan tool slow response
Common Causes
- CAN bus overloaded
- Poor bus termination
- Multiple modules with slow response
- Bus wiring degradation
- Power supply instability affecting modules
Diagnostic Steps
- Check bus termination resistance
- Monitor bus load with scope
- Check power supply voltage to modules
- Test for intermittent connections
- Remove aftermarket CAN devices
Repair Notes
Check bus termination and overall bus health. Overloaded buses cause timeouts.
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
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
U1040 on Other Vehicles
Dacia Bigster
2025-2025 1.2L I3 Turbo TCe 130
Dacia Bigster
2025-2025 1.6L I4 Hybrid 155
Dacia Duster
2017-2024 1.0L I3 TCe
Dacia Duster
2017-2024 1.3L I4 TCe
Dacia Duster
2017-2024 1.5L I4 dCi
Dacia Duster
2024-2025 1.0L I3 TCe 100 LPG
Dacia Duster
2024-2025 1.2L I3 Hybrid TCe 130
Dacia Duster PL
2018-2025 1.0L I3 Turbo TCe 100
Common Questions
What does code U1040 mean on a 2021-2024 Dacia Spring?
U1040 stands for "Lost Communication - General Bus Timeout". General timeout on the communication bus. Multiple modules are not responding within expected time.
What are the symptoms of U1040 on a Dacia Spring?
Common symptoms of U1040 include: Multiple systems intermittently offline, General communication degradation, Multiple timeout DTCs stored, Scan tool slow response.
What causes U1040 on a 2021-2024 Dacia Spring?
Common causes of U1040 include: CAN bus overloaded, Poor bus termination, Multiple modules with slow response, Bus wiring degradation, Power supply instability affecting modules.