Immobilizer Control Module Communication
1995-2005 Pontiac Sunfire 2.4L I4
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
- B0010Driver Side Airbag Deployment
- B0011Driver Side Airbag Deployment Circuit Open
B0104 on Other Vehicles
Pontiac Aztek
2001-2005 3.4L V6
Pontiac Bonneville
1990-1999 3.8L V6
Pontiac Bonneville
2000-2005 3.8L V6
Pontiac Bonneville GXP
2000-2005 4.6L V8
Pontiac Bonneville GXP
2000-2005 4.6L V8 Northstar
Pontiac Bonneville SSEi
1992-1999 3.8L Supercharged V6
Pontiac Bonneville SSEi
1992-1999 3.8L V6 Supercharged
Pontiac Firebird
1993-1997 3.4L V6
Common Questions
What does code B0104 mean on a 1995-2005 Pontiac Sunfire?
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 Pontiac Sunfire?
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 1995-2005 Pontiac Sunfire?
Common causes of B0104 include: Immobilizer module failure, CAN bus wiring issue between modules, ECM/PCM fault, Power or ground issue to immobilizer module.