CAN Communication Bus Fault - No Message
2018-2025 Fiat Cronos 1.0L I4 Flex Firefly
Description
A required CAN bus message is not being received. A specific module is not broadcasting its data.
Symptoms
- Specific system not responding
- Warning light for affected system
- Feature disabled
- Other modules compensating
Common Causes
- Module not powered
- Module failure
- CAN bus wiring open for that module
- Module in sleep mode stuck
- Fuse blown for module
Diagnostic Steps
- Identify which module message is missing
- Check fuse for that module
- Test power and ground
- Check CAN wiring to specific module
- Try to wake module with scan tool
Repair Notes
Identify the non-broadcasting module and check its power supply and CAN bus connection.
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
U1001 on Other Vehicles
Fiat 124 Spider
2017-2020 1.4L I4 Turbo
Fiat 126p Maluch
1973-2000 0.65L I2 Air-Cooled
Fiat 126p Maluch
1987-2000 0.7L I2 Air-Cooled
Fiat 500
2012-2019 1.4L I4
Fiat 500 Abarth
2012-2019 1.4L I4 Turbo
Fiat 500 BR
2011-2020 1.4L I4 Flex Fire Evo
Fiat 500 PL
2007-2025 1.0L I3 Hybrid FireFly 70
Fiat 500 PL
2007-2025 1.2L I4 Fire 69
Common Questions
What does code U1001 mean on a 2018-2025 Fiat Cronos?
U1001 stands for "CAN Communication Bus Fault - No Message". A required CAN bus message is not being received. A specific module is not broadcasting its data.
What are the symptoms of U1001 on a Fiat Cronos?
Common symptoms of U1001 include: Specific system not responding, Warning light for affected system, Feature disabled, Other modules compensating.
What causes U1001 on a 2018-2025 Fiat Cronos?
Common causes of U1001 include: Module not powered, Module failure, CAN bus wiring open for that module, Module in sleep mode stuck, Fuse blown for module.