Immobilizer Control Module Communication
2010-2021 Fiat Uno 1.0L I4 Flex Fire Evo
Description
The immobilizer control module is not communicating with the ECM/PCM. Both modules must agree before engine starting is allowed.
Symptoms
- Engine will not start
- Security light on
- No communication with immobilizer module
- Multiple no-start codes
Common Causes
- Immobilizer module failure
- CAN bus wiring issue between modules
- ECM/PCM fault
- Power or ground issue to immobilizer module
Diagnostic Steps
- Check CAN bus communication
- Test immobilizer module power and ground
- Scan both immobilizer and ECM for codes
- Check wiring between modules
- Try key relearn procedure
Repair Notes
Repair CAN bus wiring or replace immobilizer control module. Modules may need to be paired.
Related Codes
Other Body Codes
- B0001Driver Frontal Stage 1 Deployment Control
- B0002Driver Frontal Stage 2 Deployment Control
- B0003Passenger Frontal Stage 1 Deployment Control
- B0004Passenger Frontal Stage 2 Deployment Control
- B0005Driver Knee Airbag Deployment Circuit
- B0006Passenger Knee Airbag Deployment Circuit
- B0007Rear Left Side Airbag Deployment Circuit
- B0008Rear Right Side Airbag Deployment Circuit
- B0009Rear Center Airbag Deployment Circuit
- B0010Driver Side Airbag Deployment
B0104 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 B0104 mean on a 2010-2021 Fiat Uno?
B0104 stands for "Immobilizer Control Module Communication". The immobilizer control module is not communicating with the ECM/PCM. Both modules must agree before engine starting is allowed.
What are the symptoms of B0104 on a Fiat Uno?
Common symptoms of B0104 include: Engine will not start, Security light on, No communication with immobilizer module, Multiple no-start codes.
What causes B0104 on a 2010-2021 Fiat Uno?
Common causes of B0104 include: Immobilizer module failure, CAN bus wiring issue between modules, ECM/PCM fault, Power or ground issue to immobilizer module.