Lost Communication - General Bus Timeout
2014-2016 Tesla Model S P85D Dual Motor AWD
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
Tesla Cybertruck
2024-2024 Cyberbeast Tri Motor AWD
Tesla Cybertruck
2024-2024 Dual Motor AWD
Tesla Cybertruck
2024-2024 Single Motor RWD
Tesla Model 3
2017-2020 Long Range Dual Motor AWD
Tesla Model 3
2017-2020 Performance Dual Motor AWD
Tesla Model 3
2017-2020 Standard Range Plus Single Motor RWD
Tesla Model 3
2021-2024 Long Range Dual Motor AWD
Tesla Model 3
2021-2024 Performance Dual Motor AWD
Common Questions
What does code U1040 mean on a 2014-2016 Tesla Model S?
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 Tesla Model S?
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 2014-2016 Tesla Model S?
Common causes of U1040 include: CAN bus overloaded, Poor bus termination, Multiple modules with slow response, Bus wiring degradation, Power supply instability affecting modules.